I'm scared HELP I'm in crisis

18+ I had an intrusive thought and kept thinking about it but then I realised I wanted to think about it and I thought it and suddenly felt like I enjoyed it and now I feel really scared and disgusted in myself and I might have been thinking it because I genuinely wanted to and enjoyed it even though I feel awful now

Hello all. I (20 y/o female) have an intrusive thought that popped up about four months ago and has not been able to leave my head ever since and it is ruining my life. I have a memory (?) of when I was about 7-9 years old (although I really have no idea and my brain has told me varying ages even going up a few years) when I was in the shower and turned around to see my dad popping his head in the curtain to (realistically) either check on me or try to scare me as a prank. He is the most wonderful father and has never done anything inappropriate aside from this “incident” but my brain cannot let this go and is trying to convince me that this was sexual. I have always been a “daddy’s girl” but some days I cannot even speak to him on the phone because this fear that I was somehow abused is so deep in my brain. I’ll have days where I can reasonably tell myself that even if this did happen, he did not see it as inappropriate because I am his little girl, but other days it will disgust me to no end. I’ve brought it up with him once when my thoughts were at their worst but he said he didn’t even remember it happening. My brain will randomly go “hey, think about this–you’re a victim” through out the day and it’s like my whole body will shut down, my face gets hot and my heart starts beating faster and I just feel like all of the joy has physically been sucked out of my body. It often leaves me in a depressive episode. I can’t even fathom going to therapy out of the fear of my therapist telling me that this really was concerning behavior on behalf of my dad and I don’t think I could handle that. A little while back I posted this on a subreddit and someone in the comments said “this doesn’t give me a good feeling…. But it could have been innocent if you say so” and I haven’t been able to forget this. It send me into a total tailspin, if someone from an outside perspective says it’s weird then it must be??? Ever since this thought has popped up I can’t act normally. I sometimes can’t even watch movies that have dads in them because it makes me think of it, any time I hear a sex joke my skin crawls and god forbid anyone make a “sweet home Alabama” joke around me. I’ve never seen anything online about people who have experienced this too which just makes my worry so much worse. I’ve experienced OCD symptoms since early childhood however never anything like this which makes me even more scared that it is real. I truly don’t know what to do with myself anymore, every day just feels like the precious minutes I have between the times this thought pops up.

What do you do when you have a thought and you’re not sure if it’s intrusive or not? I just had one that was so strange and bad, and I can’t believe I just had it, but I’m almost afraid it’s not intrusive and there really is something wrong with me. I hate this.