1. You are not dirty. It's not your fault. Period.
2. I agree with ChipperMonkey, but given your reaction I do think it was rape. It might not be able to prosecute, but it was certainly a violation You should never feel that way about yourself and nobody should ever make you feel that way.

Definitely find support like CassyO and Chipper mentioned. Don't let a scumbag affect how you feel about yourself.