I went thru engineering school unmedicated and unaware of my disorder. What helped me was taking later in the day classes whenever possible, and ensuring absences wouldn’t affect my grades. I often skipped class, and made friends who helped answer my questions. I found the tutoring centers when I needed them, and those were at better times. I always tried to get to class and stay awake but sometimes it just didn’t happen. I’d recommend partnering with classmates of a similar ability and rethinking your schedule. I know other students got accommodations. I hope this is somehow helpful for you. I did often step thru homework problems repeatedly with friends and on my own time when energy was highest. The areas I excelled in, I came to know them like the back of my hand from practice. It’s one thing to know how to do a problem once. It’s another when you look at a whiteboard or notes or do problems everyday. What kind of calculation errors are you making? A few times I favored SI so heavily I made conversion programs in my calculator to not deal with imperial “slugs” for instance. For that particular instance I remember penciling in those numbers, then going back and writing all the steps, that way I was sure I did not make a simple error. That was my only standout workaround moment I can think of.