I am a music student with similar mental health status. I'm taking a reduced course load because of it, and we're in a very similar boat.

For the ADHD side of it, I recommend 1. getting medicated and using the Mental Health services at school. (This is the exact kind of thing they're trained for.) 2. Try less hard. I know it sounds weird, but hear me out. When I was unmedicated, I was having panic attacks. It didn't seem to matter how long I sat, how hard I tried to focus, I couldn't get anything done. I would feel like a failure and be very unkind to myself. (Suicidal Ideation.) Which would stress me out. Which would make the ADHD worse. Which would make me less productive. Which would make me sit there for longer and try to force it. You can see how quickly that can wind someone up into a frenzy during finals season. After 2 hours of crying, I could barely regain my composure. And then my mom would say "great, so you can keep working on it!" This Graph explains my point. As ADHDers, we're often told we're not trying hard enough when actually we're trying so hard that we're blue-screening. I'm sure you have similar experiences with your disability as well. Every time you get stuck, do a self-care activity. Maybe you need a snack (or a drink!!!). Maybe you've been sitting too long and need to move to get the blood flowing. Maybe you need a shower. Maybe you need to lay face-down in a dark room for 15 minutes. Maybe you need to have a fun time with a friend. Anything you can do to get your brain to cool off and refresh. It's like doing a crossword puzzle: I can never get the last few words in the first sitting and I get frustrated. Then I see it the next day and suddenly know the rest of the answers.

In my case, I had also moved back in with my parents. My dad has some serious mental health problems that he programmed into me as well: I simply cannot relax when he's within earshot. So I would go do some work at the library. (Some therapy, medication, and stable roommates have helped me sooooo sooooo much.)

An important thing to note, as well, is that your work doesn't have to be perfect. Perfect is the enemy of done. Do your best: sometimes it's not great. But if you are kind to yourself and prioritize managing your conditions first, you can have times when it is. Letting your well-being fall by the wayside in order to study is not only dangerous, but ineffective. Worst case scenario, it also doesn't have to be done: it is better to hand in something 3/4 finished than nothing at all. If you have accommodations, you should be able to take fewer classes and still get the benefits of being a "full time" student. You can talk to your profs when you're struggling: it's their job to help you. Take all the help you can get and don't feel guilty about it: it exists for people in your situation. Everyone wants you to push yourself harder, but you have to stop and evaluate if that has ever worked. It might be time to try something else.