This guy won't talk to me?

i asked this guy to the sadies hawkins dance last week but after i asked him, we barely even talk anymore. so many people came up to me after i asked him and said that he was really happy. my friend even asked him if he was happy and he said yeah. we didn't talk all that much before i asked him but now we talk even less. everytime i try to talk to him he seems not interested and the conversation always ends short. and he's never the one to talk to me first. i don't know what's going on. i'm like the first girl to show any interest in him so i don't know if that is it. please help! i started to like him after i asked him to sadies but now i feel like he doesn't want to talk to me.