I've been living with the Dizzyness you have for 3yrs. I also have gone through all the test and medications. I'm just living with it now. I can't read maps in a moving car even. Good luck to you.
It could be anxiety, or possibly some stones in the inner ear. I've read about some therapy where the head is moved in certain ways to help dislodge stones and calcium deposits in the ear. You might ask your doctor about that.
The problem with dizziness, as I learned, is that it's "vague" and there are so many reasons to be dizzy that doctors often don't know where to even begin. Recently I had sinus infections and/or allergies (still don't know!) which caused dizziness, but some of the dizzy spells were anxiety, too. After several months I can usually differentiate between which kind of dizziness it is, but sometimes I can't.
I know taking pills sucks but if valium helps with the dizziness, I'd keep taking it.
is there any chance it could be anxiety related? I know when I have had anxiety issues(not really severe). Sometimes, I dont even really feel the anxiety coming on, I will get dizzy walking into a place-could be a mall, the grocery store, or going to a party of sorts. I also had thought at one time it had to do with the bright lighting. It wasnt like the room was spinning, the best way I can describe it, was like like the top part of my body was running and my legs were walking very slow. I would get very nervous and as soon as I got back into my car and sat down for awhile it would pass.
I am not sure if volume helps with anxiety- I would think it would. So, maybe it could be. Just my thoughts though. I am not a doctor, this is just my personal experience. You can also try another doctor and get a second opinion.