So confused. Someone help please

My boyfriend is really one of the sweetest guys I've ever met. He's very loving and caring and his family is basically a 2nd family to me. I lost my virginity to him, we've both cried infront of each other, we are totally and completely comfortable with one another. But lately I've been so confused. A part of me is not happy in the relationship, and I have no idea why. I've had a lot of other problems happen recently and my boyfriends been there with me through it all, but I still am not happy. When we hang out, sometimes, I don't even want to make eye contact with him anymore. I just wish I felt that same kind of love that I did when we first started dating. I think when we first started dating, we were very alike. But over the year that we've been dating, he's changed a lot. Not that I don't like the person he is, it's just not the kind of person I would've gotten into a relationship with in the first place. I get mad at him for little things and sometimes I find his presence annoying. He really does love me so much and care about everything I'm feeling. How can I sip being such a bitch? I feel like he deserves a lot better. I don't know what to do. I don't want to lose him or his family. I would be lost. Someone help please