What to do if your man seems to be getting tired of you?

I've been with this guy for about a month now. Before that, we were just friends. At first, when we began this relationship, he could not get enough of me. We were on the phone for hours and hours. I've been staying with him at his house so often, I practically live there. Just recently, he has started to show less interest in me. Last time I was at his house, we kept bickering about little stupid things, and he would blow it out of proportion, and make the small argument in to a big thing. I finally choose to come back to my house, and give him some time to himself, but I still wanted to talk to him though. The last couple of times that I called, he doesn't have much to say, and then he tells me he will call me back. He doesn't even tell me that he misses me anymore when we are on the phone like he used to say over and over again. Whats his problem, and how can I handle this situation, and make him want me more?