you said that you are taking lots of medications for various things. We all know that meds cause side effects - is it possible that some of your other medications are aggravating your symptoms.

If you need meds, you need them but the best comment I heard was that if a med is potent enough to do good, it is also strong enough to cause bad things. It sounds like they can't find anything on tests - which is good, you don't want some nasty brain disease.
It might not be perfect but there comes a point where you have to just do what you can. Exercise and eating well is a good start. It is always your right to see other drs but there also comes a point when you just dr shop and become upset if there is nothing they can offer you.