Most Helpful Guy
Give him some time and space. Something is obviously in his head. You did your best. Let it go for a few days and try again, or wait until he contacts you.
Most Helpful Girl
Yes, I agree with the guys.. either he is talking with another girl or he has issues himself. If you did anything to offend him i'm sure you would probably be aware of that moment. So i honestly believe its best to just cut ties.