He only pays attention when i joke bout stuff?

I used to b friends w/ a rlly nice guy. Then i found out he liked me and a girl i hate liked him so she told him that i had a crush on a rlly gross guy. He got pissd off and the next day he starts dating sum weird girl! I'm pissd that now we don't even talk and he only talks to me if im joking bout sumthing. If it's a casual conversation he just slowly drifts away and doesn't pay attention to me, he doesn't even look at me anymore. I dont know wat to do. What should i do?