First of all, no matter what your sexual orientation, it's okay. Straight, lesbian, bi...there's no "wrong." It's all perfectly okay. So I hope you don't worry about that any longer.

It's very possible for sexual assault to affect sexuality, especially when it happens in those developmental stages (teen years). Honestly? I would just enjoy what you enjoy and not worry about what it means. You may not feel comfortable having sex with a guy again, but my suspicion is if you are straight (again, don't worry about the label right now), you will at some point want to try it. As for what you do with your friend, it sounds like a comfortable and enjoyable thing. As long as you're into it I wouldn't worry about whether that means you have to be a lesbian. People experiment a LOT before they figure it out, especially in their youth, and sometimes the exploring never stops. I mean I'm almost thirty and my sexuality has changed so much since I was eighteen. You're going to grow a lot, and I wouldn't waste my worrying on it.

Again, I suggest you see a therapist. They may be able to better help you puzzle out these queries. You might be surprised at how beneficial it is.

Please PM me if you need anything.