Guys and Gals could you answer this for me?

Alright... in my spanish and chemistry cl there's this guy. His name is Joey. I use to have a major crush on him last year and he seemed really nice. He likes hockey and the penguins team like me! So I asked him if he was going to the sadie hawkins dance last year in a normal conversation. He said "I dont do dances!" Then walked away. Now this year he is in my cl again, but he is not the guy I liked last year! He picks on me now, goes out of his way to laugh at the Penguins infront of my face, trys fitting in with the jerkish jock crowd, and converses with my friends when he knows I am there and knows my friends can't stand him. Why is he acting like this? What happened to the guy from last year that I liked so much?