Everyone likes a bit of a challenge, sometimes the hard to get act can be fun but when it goes on too long, people get bored and they move on.
I do agree that he should have told you himself. If, when you are back at home, you see him and his friends say something then tell them straight that if thats how he feels then he can tell you himself.
If this has been going on a while then I wouldn't have blamed him for moving on, it's fun to begin with but it gets far too boring and it's just not worth the bother after a little while. If he has moved on then it's your own fault, don't play hard to get in the future. Instead of play games, just be honest about your feelings and reduce the risk of being left with nothing.