my suggestion to you is throw out those movies and try to see a therapist.
why?
i've know a women who was repeatedly raped by her step father and her own mother didnt beleive her. so this girl went from straight and married with two kids, to telling her husband she is a lesbian and want a divorce. she dated a butch and then a guy, and now she would say she dates both sexes.

my Uncle was raped in the most horrible way as a child. he became an alcoholic, was was married, there was rumors that he is gay. it messed his mind up so much i think he drinks to oblivion.

i really beleive when this happens it really messes with the person's head. this is why you should get counseling.
please dont misunderstand me.....the outcome isnt everyone's outcome, some people are strong enough to go back to normalcy.

There is no proof any amount of mental trauma is able to alter your sexual preference. Likely you are watching Gay porn as a method of processing your feelings about what you sufferred. Given what you've gone through it's very dangerous for you to deal with this on your own. It's very important for you have someone clinically trained in dealing with traumatic events to monitor and advise you. I'd strongly advise you to meet with a therapist to help you deal with what you're feeling.

As for your girlfriend tell her you're dealing with some very serious repricussions from your rape.

Sexuality is fluid. That's an opinion held by many professional therapists.

It's not surprising that you're having this happen. The truth you'll rarely hear is that rape or molestation can result in a person feeling ambiguous about their sexuality. It's not about preference. It's about the impact of what happened to you. In Greek times, boys would often have their first sexual experiences with older men. It was part of culture. What happened to you is not part of culture, but criminality. Were most of those boys gay? No, of course not. That's the reason I bring it up.

It's highly likely that this interest will lose its momentum in time after talking with a therapist about the trauma you endured.

Good luck.