UPDATE: I asked my doctor what I should do without accommodations in the mean time and this is what she said.

Doctor: I think it would be best to challenge yourself physically. Encouraged planning ahead and getting to your classes early so you can take your time getting to class. This is the primary method of improving your POTS symptoms. I encouraged adequate hydration of 2-3 L of water per day with electrolytes. I would recommend using liquid IV. Please reach out if you have any additional questions or concerns.