POTS? TMS?

I have had an incident of rapid atrial fibrillation but recovered and have no other heart abnormalities. I have however been left with a number of severe symptoms that resemble panic disorder or TMS ( have had plenty of TMS symptoms previously).
I can walk for an hour but then get a series of rolling attacks across the entire morning and sometimes the whole day. It feels like a dump of adrenaline followed by profound weakness. there definitely seems to be a postural element to it and I am much worse standing up. I’m wearing compression stockings, which seem to help. It does seem extreme - however it doesn’t totally fit the criteria for POTS but nothing else explains the symptoms. I have had a lot of blood tests and they’re all normal. It is completely ruining my life. I really can’t do much for most of the day.
Anyone else experienced something like this?