sara, you need to report this. like bobby said, the longer you wait the harder it will be for the police or whoever to do or prove anything. i know that it might be hard to talk to someone about it because of the horribleness of it all, but in order to feel better you need to tell someone. and if you are worried about becoming pregnant than you should definitly go to the doctor. you should go anyway to make sure you aren't hurt or anything else.
i know that this is extremely hard, but you need to go talk to someone. maybe have a close friend go with you or something. this isn't your fault either. he made the decision to hurt you. you had no choice in the matter. it is his fault and not yours. you aren't responsible, he is, and he should be dealt with accordingly. besides he could hurt somebody else. report him.
i hope you are doing okay considering all of this. PM me anytime or get on AIM okay? i care about you!