I want this HOCD gone for good.

I am a 15 year old boy struggling a lot recently with HOCD. I know im young and still in puberty and probably being overdramatic. I have been watching porn since i was about 11 and have always identified as straight and always liked girls (a lot). I am currently in a relationship with a girl I love and that I want to spend the rest of my life with, it sounds stupid considering the age but its true i love her a lot. However HOCD has messed with my brain and makes me think I dont want to be with her and that im living a lie, another thought is maybe being her best friend or gay best friend, which i dont want to be. I am her BOYFRIEND not FRIEND. We are absolute best friends in this relationship and do plan to start a family some day. We are very mature but this porn has and is messing with her relationship.
I gave up watching porn over a week ago and i feel more free as a person but i cant tell if the HOCD is getting worse. It just seems more convincing now and maybe that i am gay. I know id be accepted and still loved if i was gay but im not. I love and always have loved girls, when i was 13 i felt a girl in a park and it was great. When i was 14 i properly fingered a girl but not had sex yet, im waiting for the right person, which is the person im with. I never had feelings for the previous girls but i really do with this girl. She is perfect in every way.
I want this gone and i know i can easily get out of porn for good no problem but i want the strong attraction to my girlfriend back and I want this thoughts gone. For example ive had visions of me sleeping with a man and it disgusted me but now I dont feel as disgusted as before but i know i still dont want it and this its kinda disgusting. I wouldnt kiss a man or even hug/snuggle with a man.
I need this to go sooner rather than later because I am not gay but im almost convinced that I am secretly and dont know it. I know im straight and always will be but these thoughts are so strong im worried i am turning gay and i keep analyzing every day that my actions are gay etc. I watch my favourite TV show (Doctor Who) and keep thinking i fancy captain Jack (the actor is gay so maybe thats why) but its the same with the tenth and eleventh doctor and theyre not. I love woman and their bodies and everything about them and their personalities, but this is serious and ruining my life because i know i like girls and i know i love my girlfriend. I looked over at her on call before and thought maybe i am gay, we could still have these conversations if i was her gay best friend, we could still be close. I just wouldnt be with a man, id rather be alone and the thoughts of being gay and without my girlfriend make me feel rather suicidal. What else do i do to rid these thoughts, I know itll take time but sooner rather than later will help before i make the mistake of breaking up with my girlfriend and saying im gay. cause im not but i feel i have to. I have tried watching gay porn and i felt sick and disgusted because its not me and not who i am and want to be.
There is no one like my lil princess.
Thank you if anyone decided it read all that.

 

I never got into gay porn properly before testing myself and didnt feel any arousal for it and was disgusted as where some people have felt arousal watching it which made me think i actually am gay, and my thoughts havent all been sexual, snuggling, holding hands, hugging etc. they all disgust me though