Before I got to the end of you thread I was thinking Thyroid??? But if that's been checked and your meds adjusted, my advise to you is to continue with various testing.
It's called Practicing Medicine for a reason. The doctors have to rule out this, that and the other to sometimes get you an answer. There are some things we can never figure and are given diagnosis such as idiopathic...... That just means they are stumped and can't figure out why it's happening. My brother has been dealing with this type of dx for 7 years now. Everything pointed to a stroke but every test ruled it out, go figure.
Just hang in there, try to be patient. Keep a diary of what you do, eat, drink and any OTC medications you take that you might not think could have an effect and follow up regularly with your MD.
Good luck
nj