I’m sorry to hear what you’re going through. I too have POTS but also EDS and MCAS.
What I’ve found most helpful in controlling my POTS symptoms is increased hydration (water or coconut water), increased salt intake, and avoiding known triggers. For me coffee was my biggest trigger in setting of my POTS. Once I eliminated it from my diet my symptoms have been better controlled.
Best of luck to you and please keep us posted.