I Have Experienced Vertigo About A Week Or Two Ago.

I have experienced Vertigo about a week or two ago. I first noticed when Ilayed down and turned my head to the right. I immediately got up and it took a minute or two for me to get my bearings. I started to get nauseous and cold sweats. It then happened again the next morning. Very bothersome. I called my doctor and he gave me meclizine and something for nausea. I still continued to have it periodically. I waited a day or so and everytime I layed down or moved my head it happened again. I then went to ER and they put me in hospital and stayed overnight. They ran all sorts of blood tests, MRI's hooked me up to EKG machine the entire time I was there. Still no one has suggested what has happened. I still continue to have these vertigo type issues. I went to a neurologist and he wants to run more MRI's and MRA's from my head to my lower back. I am beginning to think that no one really knows whats wrong with me.