[Veni Vidi Vici]

As Lauren said, if you tried to refuse and let him know you didn't want to go through with it, then it's considered rape. If by "tried to refuse" you mean you never ACTUALLY refused even though you were thinking it, then it would be hard to blame him. Only you know what exactly happened, so please act on it and get some help if it actually was rape. Even if you never really told him, and you feel uncomfortable, you should still go see someone to sort out your feelings. Good luck..