Most Helpful Girl
It sounds like your boyfriend is not ready or prepared for a committed relationship yet. He's got school, life, work, goals, etc. to work towards and trying to juggle all those things is certainly difficult.
He cares about you, and most probably does really love you, but he's upset because right now thats the best thing for him to do, is to not have a relationship at this time.
It may hurt him since he does care about you, and letting go is never easy. He has his priorities figured out, and he may be upset because he knows he cannot handle the relationship now, but doesn't expect you to wait around for him. I think you should give him time to calm down and clear his mind. Him only wanting you to visit every so often is a clear sign he's got other things on the go, and the relationship aspect to his life isn't among top things right now.
That being said, that doesn't mean you aren't. He may want to keep in touch, or is pondering whether it's best to cut ties and let you move on from him completely. Give him space and let him settle down. Don't contact him for a bit and leave things settle.
In the mean time, please don't think this is something you did. From the sounds of it, it's all his choice and he's trying to figure out his life and where he wants to go. You should take time to yourself, and hopefully you two can discuss this in the near future. But don't wait around for him, or let him take advantage of you. If he breaks up he cannot expect you to be there for him 24/7. I find the no contact thing works well, so let him be with his own thoughts for a while.