We know how you feel Murph.
It sounds ridiculous for me to say, "sorry your test results came back normal" but in a way, in our case, it almost IS a bummer that it didn't show something that could be easily treated, rather than this frustrating guessing game time and time again. My latest doc said, "Dizziness is very hard to treat", and I was like, "No duh!" I guess there are just so many different things can cause our dizziness and we have to keep searching for that one nugget of truth.
Hang in there - someday you will discover the problem just like we all will. It just takes time and patience.