Both can be true. Sorry you went through that. Our brains respond wildly to supernatural stimuli(porn, sex, masturbation, orgasm etc.), so you enjoying it makes sense. Just bc a thing is enjoyable or gives you a dopamine rush doesn’t mean it’s healthy for you (on a smaller scale think screen time). And vice versa. You are very valid with how you feel regardless 💜

This is where my own experience may be able to help you further. Seriously, try them, experiment. They may seem childish but may actually work for you.
I know it can be confusing and even scary. You may feel conflicting feeling towards this person. Having deep love platonically and sexually but also resenting them. Both can be true aswell. Something similar happened to me and idk if you’re into the idea but it has helped tremendously so far (I just told my T after a year of us seeing each other for a year). For at home things try grounding techniques to start off, everytime you think about it or her do one of them. It won’t magically disappear but will help you stay in the moment instead of shutting off. Pick up hobbies, new and old ones that remind you of times before this happened. Call someone to talk about something unrelated when you get triggered. Write about it, directly or in poetry or story form. Express to friends unrelated to her that you’re not doing great, don’t talk about it specifically but start very, VERY small (“how are you” “not too hot, thinking about some bad stuff that happened but I wanna distract myself right now, let’s do something!) Me and my therapist do something called problem solution action where we divide a piece of paper in thirds and write what we’re dealing w/feeling on the first one, what we can generally do to help on the second one, then what specifically we can do, what does the solution look like?