I feel that it isn't something you can change or do anything about because it had already been done. I suppose you yourself are to be blamed to go to his room and snuggle with him. Though what I felt weird about was the fact that even knowing he's your dad, you didn't stop him when he's fingering you and you let him proceed on to the next stage which was having sex with you. This either means that you either have no control over your sexual urges or deep down in your heart you wanted it and there's nobody that could stop that. My advice, get it over and move on. If not, speak to him about it and try to make the effort to forget about the entire incident. Treat it as an "accident".