Bullying is destroying my self esteem

(Not an English speaker/not US, so some collegiate bodies and translations will be different. Also, experiencing brain fog big time, so I hope this whole thing is readable.
Might delete this later for privacy reasons.)

Yes, I'm an adult, and I realize this is going to sound ridiculous, but I'm a university student and the way my classmates are treating me is making it hard to work on my studies, on top of the normal fibro challenges.

This is about the majority of my classmates and even some professors. They're not doing anything bad in theory, it's nothing concrete I could bring up with the secretary's office or student council, it's none of their business. This is a very small university, I don't know who to bring this up with, and even if I did, what would they do? Reprimand those 4 people like we're in grade school?
Also, those collegiate bodies are in part made up from said problematic people in the first place.
This is more about my lack of abilty to stand up for myself I guess.

IDK if this counts as bullying, It's just snarky comments ("there's always something with you" while laughing when they learned I went to the ER, commenting on how I'm "always" at home, ...), and overall excluding me from group activities (our class is very small, there's like 10 of us, we're kinda bound to work together for almost ever course).
Recently they've started straight up complaining about how I'm being lazy for skipping lectures and not going on educational outings ("it's just 5km, why would you complain? It's literally not a long walk", brother I have to crawl to reach the bathroom from my bedroom during a flareup. Not to mention those very frequent outings last a FULL DAY).

I swear I tried talking to them calmly, I tried explaining what this condition is and what the symptoms are, how I can't do everything that they're doing and how I need to do things at my own pace, but they've labeled me as a hypochondriac, and I can't change their mind? Why are they so obsessed with me anyways- it's not like my disability affects them in any way!

I already feel guilty 24/7 for not being able to do the things I want to do and the things that everybody else is doing, I always try my best, but I'm in so much pain (also have arthritis) and I'm so tired of having to justify it to other people who assume I'm choosing not to work hard enough. I am diagnosed with depression and a personality disorder too, I just can't handle being looked down upon by people who I already know are doing better than me in life.

I keep considering dropping out, but I also spent so much money on my education at this point, I need this degree.

I know this is all sounds pathetic, and I know this is the Internet (lol) but please be kind in the comments? I can't handle anything else right now.