Hey, I randomly developed POTS too and I'm almost positive this is diet related. I began eating extremely unhealthy, lots of refined carbs about 4 years ago, not purposely of course, but after this my heart and blood pressure have been wrecked. Idk about you but I'd say this is totally digestion related. I think that our bodies are under so much stress (I can feel the inflammation and swelling in my stomach 24/7 some days) that its causing POTS. Rarely, on really good days I experience no POTS symptoms, and it seemed like these were the days my diet was the strictest. So I would strongly recommend you order a food intolerance test (igG not igE) and start avoiding those foods like the plague. I notice i'm intolerant to more and more all the time so i recently got tested & eat extremely carefully, I'll get bouts of tachycardia if I eat something I can't tolerate. I tried Isocort too, but saw little results, I don;t think it gets to the root of the problem.