First Handjob

Yesterday I was hanging out with my crush, he's not my bf yet and we were kissing, and everything turned hot, we were in his car and he holds my hand and put it on his pants, he was having an erection, so I did what I had to do and he was moaning and kissing me, and he came within 2 or 3 minutes and then he started to act weird and distant with me.. what happened? Did I do something wrong?? I feel bad, he's not even my boyfriend.