Frustratingly Emotional?

I'm 22 and I've always been an emotional girl. It's very frustrating. My bf and I, together for over a year, constantly bicker. Sometimes over things that matter, but most of the time it's small things. For instance, when he says he is going to call me at a certain time, I expect him to. Don't say you're going to call me back in 5 minutes if you meant 3 hours. I told him just say you'll call me later. Very simple and no one gets annoyed. This is one of the most frustrating things and I can't explain why. Sometimes he'll say he'll call me back in a couple minutes and I'll say no just call me back when you're free to save myself from irritation. It works but I don't always do it. Sometimes I'll agree when he says he'll call me back shortly not wanting him to break this simple promise. Half the time he keeps his word the other half I'm beating myself up for trusting him to follow through. I don't like him calling me the next day apologizing because he fell asleep. It was happening weekly for months. It's not like he'd been working hard during the day to fall asleep on me like that constantly. I spoke to him about it often and now it's occasional. But when it happens I still get really annoyed and it's hard for me to sleep well because I'm thinking "what happened to him?" "is he ok?" I freak myself out worrying sometimes. When my bf is upset, he goes into his cave. I try really hard not to follow him in there, but when he is upset it's hard for me to be happy. He's very hesitant to discuss his feelings, but if I guess correctly what he's angry about he'll admit it, other than that he always says he's fine. It's very frustrating. He's a very moody person, and like I said it's hard for me to be ok when I know he's not. When I'm upset, he may or may not apologize, or he might flip it around so the heat is on me. Then I feel like I end up apologizing for making it a big deal and upsetting him. How do I let it go? What do I tell myself? I wish it didn't bother me