I'm dealing with something similar, and finding info on it is very difficult. For years now, I've passed out very easily. I've been told it's autonomic failure

I'm dealing with something similar, and finding info on it is very difficult. For years now, I've passed out very easily. I've been told it's autonomic failure, largely related to misfiring of the vagus nerve. I take medication for this and must wear compression stockings. Recently I ended up with esophagitis and gastritis. I experienced those awful panic feelings that sometimes would turn into full blown-panic attacks. The chest pain, floating feeling, flashes of vertigo etc.. All related to vagal stimulation from GE phenomenon. Omeprazole helped significantly, as well as dicyclomine. Keeping a detailed food log and marking symptoms has helped me find problematic foods as well. All in all, it's been 6 months and improving, but it's absolutely miserable! Just knowing that you can be sitting there perfectly calm, then suddenly jolted into a panic attack is a daunting thing to deal with. I don't have much to offer in the way of information, but it is good to know that there's other people out there suffering from the same/similar things.