You may or may not have been raped. From what you say, it seems more like a drunken mistake than rape. Unless the girl forced herself at you. The problem with drinking till you lose control is that you do thins you're not aware of. It's hard to say.
Not long ago a judge said that a lot of women especially come to the court claiming they were raped while drinking a lot. As much as sympathy she had for those people, there's not much that can be done.
And I'm not saying that it's your fault since you'd be the victim, but I'm not sure if I'd class this as rape... I mean, you didn't know what you were doing but you probably gave her consent, unless she is lying. So it's a mistake but not rape (probably). Rape is a violent matter and it messes people up psychologically especially.