Why isn't he calling?

Okay, so I started talking to this guy. We had an awesome night together at a concert with a group of people and really hit it off. We've met a few times before, but this time we kissed and cuddled and stuff (not sex). He lives 4 hours away from me. after the concert he would call me every night and we would talk and flirt for like an hour, one night he called me four times. This went on for about a week and a half. I was back down where he lives for a few days, and one night he invited me over. So I went over and we did more cuddling and flirting and tickling and such on the couch, it was really nice and cute, totally innocent and pg rated, and he didn't seem to mind. He walked me outside, kissed and hugged me goodnight, and I left. After that night, he stopped calling completely. I waited for a few days, and then decided it was a good amount of time for me to question him about it via facebook messaging. He told me he has just been really busy with a job at work, so I accepted that and left it at that. It has now been two weeks since I wen't over, and he still hasn't called, not once. It is difficult for him to call me because he doesn't have a phone of his own at the moment so he always calls from his mom's cell. What happened? Was it something that happened (or didn't happen) when I went over? He had ample opportunity to make a move if he wanted to.. Is he really just THAT busy? I don't know if something happened to make him change his mind or if he really just hasn't been able to call. He hasn't been on facebook in like a week, so he must not be lying about being busy, but so busy he can't call and say hi? I don't want to question him again because I don't want him to think I'm needy. Any ideas what's wrong (or am I overreacting?) and what to do?