At the first college I went to, which I later dropped out of because it was austere, cruel, and awful, I went to a little high school tour day thing. They had a seminar for prospective students; one of the faculty talking had people coming up and asking him questions at the end, in a classroom. This was fairly informal, but it had this stuffy bullshit ‘prestigious,’ ‘serious’ academia vibe like, ‘ooh, this school is really tough, gonna be really miserable for you.’
And I asked the speaker at the end, like, ‘So what do computer science majors actually do day to day in classes? Like, what sort of projects do they work on?’ Completely earnestly, because I was curious because I thought it’d be a cool answer. And he literally said to me, ‘That’s really more of a lunchroom question,’ in the most pretentious tone I’ve ever heard in my life. good christ.
And I went to that school! And it was miserable! Honestly, I didn’t even fully understand or realize how utterly rude and pretentious this dude was being to me until recently. I thought I was asking a ‘silly’ question, but NO! NO, absolutely not, it is absolutely a valid question at a college tour day as a little high school kid. And this guy genuinely seemed so offended and put off that I’d dare ask him a silly question, like he was above answering. I genuinely did not have the brainpower at the time to process such an upjumped pretentious moron.
Sounds like you have the thought stuck in your head, it can help to complete a thought record (I would recommend this 7 column one from get.gg https://www.get.gg/free-downloads-alphabetical-list-of-cbt-worksheets-information-sheets-n-to-z/ ). Doing something like this a few times can weaken the thought by addressing the emotion behind it and the lack of evidence for this on an ongoing basis. If the emotion is shame or guilt say, by finding evidence of times where you were very competent and confident can weaken those feelings by showing this as a one off.