Accused of "snitching"?

I dont get it like 4 years ago when i was in school i got into some trouble with the cops. A guy i thought was my friend sold me out and I got arrested. He gave up the names of all my friends and ended up not getting into any trouble. I got expelled from school and had to go to court and everything. A couple months after that i tried calling some friends and they were all mad saying I sold them out. I havent seen any of them until last week one of moved next to me. ANd is trying to start problems. WHat would You do?