Can something PLEASE help me understand what happened with this guy?

I met this guy 2 weeks ago. We hit it off in a major way. I didn't get his contact info though. Well, he managed to find me on FB a few days later. He IMed me like 5 minutes after I accepted his friend request. He asked if he could take me out on a date. We went out the next night and it was really great. He texted me the following day telling me he had a great time. Texted me constantly! Asked me the next day if I wanted to go out. We went out. It wasn't as magical as the previous date but it was just an off night. I didn't hear from him again after that. I saw him out last night and he totally ignored me. I walked up to him at the end of the night to just say hello. He immedietely told me he just got out of a relationship, he was VERY cold. I don't really know what I did wrong. He was the one who pursued me. I was not overbearing or crazy towards him at all. What happened here?!