Please help me

Ok so I had this thing with a boy , I'd liked him for ages and he said he liked me , we met up and we did stuff a lot of stuff , stuff I had never done before. After that I didn't like him because he forced me into it even after I told him I didn't want to do the stuff. I told my close friends and then another girl who Im friendly with at my school who's also friendly with the boy guessed what had happened , which I denyed but she was like 'no it is true because he told me he done stuff with a girl but never said who' and now I'm really scared she's going to go tell her best friend who will tell everyone. I know it's my fault to have done the stuff but I just don't want it to go round my school and everyone knowing. Please help me