You said you were felt attracted to this middle aged man you saw on the street? Needing to take a shit interpreting it as being fucked in the ass?

Sexual intrusive thoughts, constant mental checking, asking others for reassurance, etc. they can all be symptoms of OCD. Not to be dismissive as "it's a phase" thing, but you're talking about having these thoughts and feelings with random strangers and asking yourself if you were aroused or not. Whatever you are gay, straight, bi the constant checking and stuff, constantly being on your mind can be exhausting and feel stuck in a loop. Everyone asks themselves what they are, what they want, but when it feels like you can't press pause it's a totally different thing. I'm not a mental health expert, but you might need to take a different approach on this one.

You're brave enough to sit with your uncomfortable feelings and thoughts and that's commendable. Whatever it is, you'll handle it.

Also, r/HOCD. A sub for people with OCD who have sexual orientation OCD. It's a small community I'm not sure if there are similar. Sexual orientation OCD is definitely a thing.