It's frustrating, feeling like you're being held back from something you want for seemingly no reason. I started my mission papers on July 3, 2011. I wasn't able to complete them (i.e. have my final interview with my stake president) until February 8, 2012, and the actual call didn't come until March 22. It seemed like most of the other guys on my floor in Merrill Hall had started their papers, finished them, and received their call by the time I finally got mine. It didn't seem fair. I mean, yes, there was that whole time when I was worried that I was wanting my mission call for the wrong reason and so I prayed that I wouldn't get it until I was ready, but I had worked past that, hadn't I? I felt like I'd changed and straightened things out, but it was still months before I got the call.
Now, with hindsight, I can see why such a wait was necessary. I understand how the timing of receiving my call worked out with events on my mission and my life in general. However, that doesn't change the fact that that entire period of waiting was basically the worst.
Now, there are a couple of points of your question I'd like to focus on:
How can I receive the same spiritual blessings and inspiration that those who have the opportunity to participate in endowments when I am in the baptistry?
In a sense, you can't. A particular scripture comes to mind:
And when we obtain any blessing from God, it is by obedience to that law upon which it is predicated. (D&C 130:21)
Stay with me here. While I'm entirely aware that this probably wasn't what you were wanting to hear, realize that this applies to more than just you. If we haven't made a certain covenant with God yet, we're free from the obligations of that covenant, but we also cannot access the blessings associated with it. As a single man, I'm not entitled to the same blessings and inspiration that my married friends are as they strive to keep their marriage covenants, no matter how much I may want those particular blessings. It happens to all of us.
Maybe that doesn't help, but consider this: God has a plan for you, and the honest mistakes of mere mortals (trying to do their best) are not going to interfere with that plan. Try to imagine Heavenly Father saying this: "Well, darn it. If only [Patience] were endowed, they'd be able to handle these trials coming at them right now, but Bishop So-and-So didn't get the right signal, so I guess they're just going to have to suffer through it. Such a shame." Does that strike you as the language of an all-knowing, all-loving, all-powerful Being? It certainly doesn't for me.
I should probably just cut to the point: God knows you, He loves you, and He's aware of your situation. With all of that in mind, He has given you all the tools you need to succeed in your life right now. All of the channels of revelation necessary to receiving the inspiration you need are already open to you.
"But Frère, if [Patience] already has all of the tools they need, why isn't the inspiration flowing? Are you trying to imply that they're doing something wrong?" asks Daemon Rubik (that's what I've chosen to name the devil's advocate that asks me questions when I write answers like this. He and I talk a lot).
No. That's not what I'm trying to imply. I'm almost certain that that's not the case, and here's why:
It seems like I rarely get inspiration from spiritual activities. In fact, I might as well just pare that down and say that it seems like I rarely get inspiration. I read my scriptures regularly, but I don't get much out of it. I try to pay attention during church, but I often doze off or my thoughts wander. Ditto for the temple. There were only one or two things that I thought were relevant to me in General Conference, and I haven't done much to apply them.
Now, I'm not trying to imply that I'm perfect or doing everything right (in fact, based on that description, I probably seem rather imperfect to a lot of you). A lot of the time, I wonder if there's not something wrong with what I'm doing. Compared with the revelatory feast that was my mission, my performance seems very, very poor indeed.
But here's the thing. In my praying and pondering and trying to sort out my own situation, I've come to believe that experiences like yours (and mine) are less of the exception and more of the rule. Are there people who receive visions (be they literal or metaphorical) daily? Probably. I imagine the Apostles do a pretty good job of that. That's partly because they have more practice and experience at it, but it's also because they need it more. On their shoulders rests the spiritual responsibility for the entire church, and they need a whole lot of revelation to handle that responsibility (and, from what I gather, even they sometimes have doubts that they're doing it right).
You and I don't have that kind of responsibility and hence that kind of need. That's not to say we have no need; I'm trying to figure out my major (and by extension, my career), find a way to survive this nightmarish semester and somehow also squeeze in a date here and there. Heaven knows what you've got going on, but you also have a very real need for divine guidance in your life.
Going back to what I said before, I believe that God loves us, and I believe that God is giving us exactly what we need in terms of guidance and revelation while still respecting our agency. It often doesn't seem like it, but that's probably because, in reality, God knows our needs a lot more than we do. I'm sometimes glad that my prayers aren't always answered in the exact way I want, because with my imperfect judgment I'd almost definitely mess it up and squander the divine aid given me.
Let me shine a light on another point of view. Earlier, I was very careful to include the word "seems" when talking about my spiritual habits ("it 'seems' like I rarely get inspiration"). That's because of a conversation I recently had with Mère Rubik. I was expressing to her some of these frustrations, and she wisely observed that I may have been guided without even realizing it. It made me think of an idea I had on my mission. If we're living the right way and doing what we should, we invite the presence of the Spirit into our lives. If we do it consistently enough, we may become so used to the Spirit that we might not recognize its influence in our lives. If we're on the right path, we probably don't need large, drastic messages from God to tell us what to do. More likely, we just need little spiritual nudges in the right direction to keep us on course, and those nudges are often imperceptible.
So, here's an idea: think about how the past week or so. Think about some of the times when things went right. What led to that happening? Was the choice in front of you obvious, or did you just have some sort of gut feeling that it was right? Doing so may help you discover previous inspiration that had gone unnoticed. If you do stumble upon encounters like this, be sure to thank God for them. Doing so will help you recognize them later on.
At the outset, I did not intend to write that much on that first question from your submission. Hopefully it was relevant. On to the next one (which I promise will be shorter):
But how do I keep myself from feeling like a little kid when all of my RM friends plan a temple trip and even if I go with them I wouldn't be allowed to go with them inside?
That's mainly an attitude adjustment. No one is making you feel like a kid except you. Recognize that we're all at different points, spiritually speaking, and it may just not be time for you to move on to other things right now. But, if they plan a temple trip, that by no means implies that you can't go, too. Do some baptisms and confirmations while they're in a session. Now, you probably won't take as long doing that as they will in the endowment, but that doesn't mean you can't capitalize on the rest of the time in the temple. Try reading the scriptures in the waiting room for longer than you normally would, or even praying for an extended amount of time. That was actually something that the AP's in my mission recommended once: setting aside an hour just to pray. While I didn't get the most out of it (I was even sleepier as a missionary than I am now), I think the premise is sound.
That ties into my most general advice for your situation: if what you're presently doing isn't bringing the results you want, do something else. Try praying/studying for longer periods of time or at different times in the day. Study with specific questions in mind or research specific topics. Say a prayer giving thanks for everything you can possibly think of without asking for anything else in return. Pray/study for your family, your roommates, your ward members. Pray to see opportunities to serve and love others and/or to share the gospel with them. As you've read that, you've probably rejected some of those ideas, but hopefully others came to mind. God wants you to succeed, and He will more than match any effort you put into your search.
Again, apologies if that was a lot more than you expected. It was a lot more than I was planning to write, and yet it felt right to do so. If you want to keep talking, feel free to shoot me an email.