I am not going to go as far as to say you "raped" this girl, but you did know full-well that she was having inner conflict, and you allowed it to continue (even if she did eventually participate her share in it). I think this does not make you a BAD person; however, I can't say that you've displayed any nobility either.

You were fully aware of her inner conflict, consequently you knew that by having sex that she would be faced with feelings of guilt, confusion, etc. You knew that and continued, so we can at least say that you did not have her interests at heart.

I think the best thing you can do at this point is to back off and give that girl space to process her own feelings on her own time. She will come to you if, or when, she feels ready. I think an apology is owed, and you are the best judge of the situation to know how you can give an apology while also giving her the space she deserves.