I'm sorry you're not jiving with vet school. It's hard, it's long, it's unforgiving. Not sure if you just want to commiserate or want some true advice. In case of the latter, I would say that identifying what the causes of the overstimulation and what seems overwhelming to you is a place to start.
As an example, I never missed a class in first year 1.0. Like I went to 98% of my classes for the whole year in addition to all the clubs and such. When I repeated first year, I went to class for the sake of being socially integrated with my class, but didn't go for the benefit of the lecture unless they were a prof that actually taught and expounded on their slides. Otherwise I put in headphones and made my own flashcards or outlines (whatever worked for that subject). Massive improvement in my grades, like 5-6%.
Next was realistic expectations. I went in wanting to be top of my class, being a badass and such. Obviously I repeated first year 🤣 I found my expectations if myself too high and had to acknowledge and accept that. So then I settled for "pass". Stress greatly improved and now I live by, "Do the best you can with what you have".