I agree with anotherswede, but also have to add; whatever you do don't blame yourself.
Too often people get manipulated into feeling guilt for allowing others to violate them, it is never your fault when someone does something you didn't want and that you are not happy about.
People take advantage of others when they are vulnerable, they shouldn't it's wrong, and it's not something you can or should forgive in someone that presented themselves to you as a friend.
People that truly care about you would not violate you, allow you to be violated, or manipulate you, whether physical, mental, or emotional.
For that reason I have nothing to do with my family.
You are lucky that you were able to see it for what it was, and not be manipulated into accepting it and allowing it to be a gateway to further violation.
Some would say you should take this to the police, but I think first stop has to be a TRUSTED friend or relative, then a counsellor or therapist, then if you are ready or feel it necessary think bout laying charges.
That sort of thing is just not okay.
Ever.