There are a few of us here that suffer from dysautonomia, either AN, POTS or some cases where it may not be too clear. I have suffered from a host of problems after having a mycoplasmic pneumonia almost 20 years ago. I also suffer from "connective tissue disease" (with Raunauds), fibromyalgia/CFS, and have been diagnosed with small fiber neuropathy through skin test. I also suffer from dysautonomia and am having testing done to see if a cause can be found. My neurologist feels it is inflammatory and related to the SFN. Gastroparesis often goes along for the ride. I had a real problem with it a year ago and manage it now.
Sometimes, there is no problem identified as the cause of these conditions. There may be an antibody responsible for an inflammatory autoimmune illness, but many times the 'antibody' cannot be identified. That is more-or-less where I am.
Key is managing the symptoms and that can take a great deal of experimentation with different meds.
I have started exercising every other day to see if it makes me feel better. Sometimes, I have a hard time getting off the couch because of how lousy and fatigued I feel. However, I am getting pis*ed about it all so I am exercising in the hope that it will at least make the flares shorter lived.
I wish you the best and remember, you are not alone.
Mere