Why won't he change when he says he will?

I have been with my boyfriend for like two years now. He’s a great guy, he is loving, always does everything for me, cares for me, and I really truely believe he has never cheated on me, I mean either that or he’s REALLY good with his words. But…he left to go back to school recently and stopped calling me, no texts no nothin. He called me this ONE time but that was late as hell like 3 in the morning or somethin. I text him telling him that maybe we should break up…or at least take a break and THEN I got a call from him saying we cant break up baby I’m sorry your right, I should call you and I’m going to do that. I know he has school and lots of work and I know he has friends and a life. But why can’t I just get a call at least before he goes to sleep on the weekends at least when he shouldn’t have much or any work to do and when he should be done hangin with his friends? It makes me feel horrible because I feel like I will never meet another guy in this world who makes me feel the way he does but it’s like he doesnt care like he says he does, such loving things he tells me but then this happens and I dont know what the hell to believe…it hurts horribly…and he didnt change at all after he told me he would. I really dont want to bug him about it anymore. I know he is only 19 and still a young boy whose friends are still the most important thing to him, but does that really mean that I have to be left with nothing? WHAT WOULD YOU DO if you loved someone more than anything, if it felt like there was nobody else in the world for you but that person seemed to lose interest in you…I feel so trapped.