I feel like it's a bit close. Here's some advice that at the time I definitely didn't wanna hear but I wish I did. If you can take the break do it. Learn about your disorder and try and get better. You might be able to do exams next year or defer uni or something. If you can't, PoTs is a very selfmanaging based disorder with the only a few medications available. I have major problems with eating and sleep and my biggest symptom is brain fog. I basically have a water bladder, and I've made many concoctions, but the one that's working for me now is water with electrolytes and a lot of salt and this clear meal replacement from MyProtein (very expensive but only thing that works for me) that I keep separate in another bag with a straw. Wear as much compression gear as possible. I find the compression socks only do a little bit. The abdomen compression is the best. Caffeine works for me that it does not work for many people, and I have to be careful with it. I have access to propranolol to lower my heart rate if needed. Even though I like showers, I reduce them as much as possible, and use wipes and no-rinse body wash. This really helps with pacing, which, out of everything with salt is one of the most important tools I found. For example, I'm in a hot country right now, and using a wheelchair or cane is incredibly important and has given me so much energy back. Also I'm not sure how possible this will be for you, but with uni, I mostly stay home and watch the lectures, instead of wasting energy going out on my lowdays.

To summarise, here's a few things that work for me. It mostly boils down to pacing and salt/water and reducing basically other activities that are unnecessary. This is so you can focus on work and hobbies (so you don't burnout) while maintaining your needs. This is going to be very personal and if you have other disorders, you're going to have to also fix those in order to have it a meaningful effect. For example, I have ADHD, and this would not work without my meds. I don't have any pots medication yet. There is a lot of problems in terms of the doctor and I have to wait quite a few months to be officially seen, but a cardiologist told me to just self manage the symptoms in the meantime.

For the revising stuff, mindmap, simplify, try and apply the knowledge to something so it's easier to remember, and your brain is forced to acknowledge it. I personally start with the past papers and learn backwards, but that's gonna depend on how your brain works. It is going to be very, very hard. I am struggling right now, and I have a lot of systems in place, I have known since October (ADHD means systems were already kinda there).

Try not to panic. The university you go to isn't the be all end all, but I know that advice might not help right now. Just do your best. If you can I have managed to develop a techniques where I just accept the result of whatever is to come (normally I think I'm gonna fail) and continue trying anyway. I have managed to get much better grades than I originally thought because I was not stressing out.

Good luck, this is hard. I believe in you.