Did I Do Something Wrong?

My boyfriend and I have been planning to had sex for the first time. We've been together six months. We are both 18. We started making out and when it came time to put it in, he started hyperventilating! I tried to calm him down but he locks himself in the bathroom. I here him hyperventilating and then vomiting. After about 30 minutes he comes out. I asked what was wrong. He said he's not ready. I asked why and he said he doesn't want to talk about it. Did I do something wrong? We were sure we were ready.