Reassurance isn’t reassuring after awhile?

so I've been trying to do what my therapist said while she's on vacation for a few weeks and do some of my routine exposures. One of them is watching tv and not looking away when there is children on screen. I tried sitting through a preview of a shows first episode that featured a young girl in a Victorian outfit with blonde hair, and he had very ghostly white skin and powder pink lips. It was a ghost show, which is the kind of genre I usually like, so I wanted to try and enjoy the clip. And my therapist always told me to "not appraise the thoughts, our goal isn't to avoid them, but to let them pass" but as I kept watching, I kept getting mental voices telling me that "she's pretty you want to kiss her" and I felt almost frozen in my seat? I felt a kind of anxiety I haven't felt in years, but I tried to continue to watch the clip and let it pass, but I couldn't. I felt this mental need to go back and "check" to really be sure if I was attracted to her, I pictured kissing her and idk if it even counts as an intrusive thought atp? I felt like if I were to have the thought and then prove myself I was grossed out by pushing it away I would feel better, but it didnt. My brain just kept telling me that I wanted her and it was very much on purpose to test to see whether I felt that way or not and it did and I kept feeling that horrible form of anxiety that makes your face hot and I don't think I was really TRUELY attracted to her but it's like a fucked up twisted form of attraction that's false but feels real at the same time? Idk if that makes sense... idk, I'm trying my best but I feel like I NEED to think the thoughts, letting them pass isn't enough. Or like the thought will stick in my brain and it'll keep going like a mini movie playing in my head and it feels like almost like I'm fantasizing even though that isn't what I want to do. I feel like I have no choice but to push them away or else I'll have a horrible realization... idk... I've been struggling with this for 5 years now. I don't even know how to properly articulate how I feel in those moments it's so confusing that I don't know how to describe it to my therapist. How do people just lable their feelings on things so effortlessly? Why is it so hard for me? Idk I don't really want reassurance bc it won't help but I just want to feel like I'm not alone in this.

Have you ever been feeling okay and then suddenly an old intrusive thought comes back but worse and you can’t seem to get past it as easily?

Any tips on whenever you’re getting that intrusive thought, what can I tell myself without reassuring myself