Have you had MRI of your spine and brain? I have a very bad back, cervical fusion in 2012, C4-6, having c2-4 done in a couple weeks and L4-5 done last year. I know chiari malformation can cause POTS and a CSF leak can mimic it too, but when you say you drop things, I had that before I had the C4-6 fusion. I still have neuropathy in my lower legs from the L4-5 fusion, but the drop foot improved a lot. I still have bad areas of my back though. L2-4 are bad and T1-2 has some disk herniation. Something to think about. Funny thing is, I lost a lot of weight over a year and half, 170lbs. Went from 382 to 211-212. I am 6'5, but the toll the excess weight on my body is something I cannot escape. I don't know why I got POTS, all this started with GI problems late last may and POTS hit around christmas. The only thing I can think of is a poorly treated H Pylori infection when I initially had GI symptoms.