Dealing with POTS and Chronic Fatigue Syndrome: How to Tell the Difference?

Honestly, I'm not sure. I have a POTS diagnosis and have been symptomatic since childhood. I remember nearly fainting when we had to go play in nursing homes for orchestra, because we had to stand and it was so warm in those places. I do have a ton of fatigue, but I have other diagnoses that could cause it (MCAS, EDS, circadian rhythm sleep disorder, malnutrition/failure to thrive, etc) so it's kinda hard to say for sure what the cause of my fatigue is. Looking at the symptoms, I match with a lot, but like...is post exertional malaise due to CFS/ME, or because I am not getting adequate nutrition, dealing with MCAS reactions saps energy, and I don't get enough sleep or refreshing sleep due to my sleep disorder? I do know someone who has a diagnosis with both, and they have verrrry little energy, crash a lot after doing very little activity, and spend a lot of time in bed. But still try to get out and do stuff, even if it is just five minutes in the garden at a time, because at least that's something. Or they participate in stuff like advocacy that they can do whenever they're awake and have energy because there aren't set hours. And I know they frequently use a wheelchair or scooter to go out with their partner and friends, or to walk the dog, and that saves a ton of energy for them. I also use a wheelchair (for EDS, MCAS, and some undiagnosed muscle issues that make it difficult to walk even with braces and crutches), and I can do SO much more if I use my wheelchair vs try to walk (with or without braces and crutches). I know not a ton of doctors support wheelchairs for POTS, though they might go for the scooter idea so you can take your dog out or go for a walk with friends for needed socializing, while preventing a full drain of your energy. But fatigue is still a huge issue for me, especially with so many things that can cause it, so I have just come to understand that I will never get everything done that I want to get done in a day, that I'll need to alter plans on the fly or sometimes beforehand if there's time to discuss changes to whatever is going on, that I will sleep 9-14 hours sometimes and that's okay because otherwise I'd feel even worse and there's nothing wrong with that even if it doesn't match society's idea of how much sleep is "appropriate". I have talked with a sleep doctor and that helped me some, especially with knowing what other people experience and what some strategies are that I can do to help manage sleep and fatigue. I saw a sleep psychologist once too, who claimed he could fix my sleep issues completely if I followed his plan..and I never went back because I didn't see a point because things like malnutrition, hypoglycemia, MCAS, POTS, and other health issues influence my ability to sleep and do things so much that I didn't think I would be able to follow his plan. Maybe I would be able to...idk. But at this point in my life and in managing health issues, it just didn't seem feasible. Hopefully they'll be able to get you on some meds that will help with POTS, and that will alleviate some of the fatigue and feeling like you're going to pass out. We haven't found a POTS drug that worked for me (other than daily IV fluid infusions and a lot of salt), but I know other people who have had great success with meds once they found the right one. If they prescribe something to you and you give it a decent chance (usually two weeks, unless you have really adverse effects) ans it does not seem to do anything, don't be afraid to go ask for a different drug to try. There are different ones and different classes, so you have options, and your doctor should be able to help you work through and figure out what might be the best option.