Dealing with pots (severe bedridden)

Hello, I've been bedridden for 45 days following several major crashes. I limit my steps to 400 per day. My wife does everything at home, which is difficult. I'm in severe/very severe pain: I can eat, walk to the bathroom, watch TV for two hours, and work on my computer for one to two hours without too much trouble. The real difficulty is when I stand up. I've had this problem for a year and I thought I just had pot and not ME, so I started cycling... it got worse... When I stand up, I go from 75 when sitting to 120-130. So I sit down after two minutes or even one minute. My blood pressure is roughly normal. I drink 50 cl with an electrolyte drink and more than two liters per day. Should I try ivrabadine? Fludrocortisone? I'm afraid the fludrocortisone will raise my blood pressure too high; I'm sitting at 12/8. What do you think? I don't have an appointment with my specialist for at least two months... but I can always ask my family doctor.