can somebody explain why our brain does this?

i was thinking abt the time my ex friend randomly sent me without consent illegal stickers to mess with me me and while i didn't look at it because i didnt want it i read through the description what it was. now my brain is telling me intrusive obsessional questions such as "why is it wrong though?" and trying to convince me this thesis with "think about it", trying to make me doubt my belief. it's a question to which my answer is "obviously wrong" as for me is a dogma but my brain keeps knocking on me and persisting with multiple "why?" and "why?" and "but why' and i feel more and more uncertain, almost like believing it while not wanting it and not liking it. im not attracted to that shit, i didnt enjoy this thought process i was bothered and anxious abt it, not liking it but still distressingly seeing it through. but the obsessional question still persists, and it scared me a lot because i gave it value, i gave it validity by hearing it out and perceiving the possibility of it being true, even though i dont want it at all, I BELIEVED IT!!! i know it's clearly ocd, but i cannot tolerate the fact that i gave it validity and believed it even though not agreeing with it at all. what i want is for it to be wrong and for me to be confident about that, but this thing still happened. im very stressed and also disturbed and feel horrible for believing when i dont want to. i also had a forced egodystonic sudden thought like "huh why would it be wrong if one just did it for <pleasure>? doesn't make sense" in response to a particular disturbing ocd question but that was made it seem and placed as a generic question... as if i didn't want for it to be wrong under that generic circumstance and that is bothering me a lot, im afraid that even if it is egodystonic and i clearly dont believe it is right as i think with more effort and remove that cloud of momentary irrationality, that i still genuinely thought that for a moment, that that thought still happened, but i also remember it being an induced, automatic answer... maybe it's because it was formulated in a manner that made it for me to answer that way. maybe it was just an impulsive fast thought in reaction to the generic aspect and premise of that disturbing wrong question that wasnt thought enough and it doesn't really reflect truth and reality of what i believe. i cant tolerate that i had that thought. was i just manipulated into hearing out that question and i automatically believed that doubt and agreed with the doubt? i dont like that at all. I don't believe it is right, for me it's wrong and disgusting, so why did i have a suspension of the disbelief? im stressed the fuck out from this single moment. i hope that thought was intrusive, but also i know that i don't like it and dont agree with it, but still cannot tolerate that that thought took place. i don't know what to do. i cannot tolerate that i believed this ocd horrible take (even though not agreeing with it). im traumatised by what my ex friends did to me. im hoping it's one of the case that i call condition of existence, that in order to check a intrusive question your brain automatically sets it as "true" in the realm of that thought.

I hate this! so f-ing annoying! my brain gets over one “what if”, then goes onto the next immediately. It’s like my punishment for feeling and sort of peace or relief. for example, I did a compulsion yesterday trying to see if I did anything bad/inappropriate, I eventually got relief and was like I didn’t do anything bad but then today I did the compulsion one more time just to make sure and then I finally got relief and then my ocd latched onto the compulsion I did today and was like “what if u did something bad/inappropriate but don’t remember” like wtf. this JUST happened. it feels like i forget things immediately!!! Idek if this makes sense im just venting this is so annoying

How do you know the difference :( I genuinely cannot keep living in this torment. it all started with an ‘intrusive thought’ where I had like a hazy flash of something reading an article. and I remember thinking ‘what if’ and ‘what is this’ and then that intrusive thought turned into me ‘remembering’ something else. which caused me panic. then I started trying to find evidence because it contradicted what I remembered this entire time. this was last year in like september. fast forward to march this year, it came back up- but this time stronger and with more ‘details’ and what nots. and I’ve been ruminating on it since then trying to remember and connect and It’s like I’ve added all of these details. but are they real? or is this just my OCD? I just feel like if it were real I would have never been able to keep it to myself. but also what if it was so traumatic that I blocked it out? because it all makes NO sense for me to do something like that. but it also fits what I was thinking at the time. idk