I would very much echo everything spaghetti said.
The main thought I would offer is to let go of the idea that you need to "fit in" to any arbitrary institution. You have struggles--don't we all? But you have (as you note!) many strengths and joys as well. And you are benefiting from one of the most valuable aspects of attending an elite institution--like-minded friends (and without paying the Ivy price tag!).
Practical suggestions: I posted some to a similar question on taking AP tests that you asked when you were in high school, which I'll re-word slightly here:
1. create mini-races or targets for yourself, to take advantage of that fact that you can "sprint". So instead of looking at the AP exam assignment as multiple hours of sustained attention, conceptualize it as a series of one-page mini-tests. So, for example, part I of the AP Physics exam consists of 50 multiple choice items in 80 minutes. Instead of thinking of it as 80 minutes of nonstop work, think of it as 4 20-minute intervals. In each 20-minute interval, you might target completion of 12 x number of items. Spend 18 minutes of focused time, trying to get as close to 12 items complete as possible, and then give your brain a 2 minute break. Or use 8 10-minute intervals: 9 minutes of focus, followed by 1 minute of break, working on 5-6 items at a time. I'd suggest trying this on a few practice tests, and seeing how it works for you, once you get used to the rhythm of it. You won't be able to use an audible timer in the real test session, of course, but you can use a watch, and just mark the fifth item with the target time. Use the break minute to stretch quietly in your seat, practice breathing, shake out your hands, do progressive relaxation through your body (to release tension), or whatever nondisruptive activity you can do in your seat that helps you refresh yourself. And then dive back in for another focused period.
2. STUDY GROUP: I know spaghetti has already said this (a few times!), but I cannot emphasize enough how valuable this can be to your type of learner. You don't even have to read all of the chapters out loud yourself. I suspect that you will get quite a bit out of the discussion, with specific gaps in your knowledge or understanding that might emerge in conversation acting as directions, sending you back to the text for more focused close reading.
3. One thing at a time: it's easy to get overwhelmed by the amount of work you need to complete before semester's end. So don't try to tackle it all at once. Chunk or group them into smaller, more manageable lists, so you can (physically) check them off, with that nice feeling that comes when you complete a list (a short list, please).
4. Create artificial deadlines: e.g., make an appointment with someone to do something fun, but only on the condition that you have completed x,y, or z task by then, so you'll have to call them up and cancel if you're not done. Sometimes, not wanting to disappoint someone else can be a productive motivator.
5. Set up your own behavioral mod/positive reinforcement schedule/gamification of necessary tasks: you can reward yourself with something small but fun for every x number of minutes on task, or for every task (or section of a task) completed. Or earn points towards treating yourself with something medium sized at the end of the week, or bigger at the end of the semester.
Keep in mind that the purpose of these suggestions is not only to help get you through any given semester, but also to help you identify and practice to fluency executive function strategies that work for you.
If you have the resources for it, you can also consider hiring an executive function coach. There are several in your area who specifically work with college students. BeyondBookSmart is one of the bigger ones, but there are lots of smaller providers too. You may also be able to find some referral suggestions at your university's learning center.
And fwiw, I never practiced my instrument so much as when I was supposedly studying for graduate school exams (not in music)! I've also made a conscious decision to place myself in a profession with constant deadlines of a magnitude that works for my particular level of procrastination and sustained attention. I appreciate your encouragement to parents of younger 2e learners--my encouragement to you is that there are those of us even further along on the journey who have learned how to manage ourselves and our environments more effectively. You will too, but it will take time, and it won't look exactly like anyone else's way of doing it.
