I think you're already at the hospital, and I'm so sad I missed you before you had to go! Gary had a tumor removed from his head two years ago. He didn't have incidents of vertigo or unwanted sleeping episodes, but he had insanely painful migraines. He is TERRIFIED of doctors and hospitals, but came through with flying colors - after two years of searching for the problem. I hope you don't have to suffer that long.
I'm praying it's not a brain tumor, although, again the advances in surgery and technology have come so far that if that is the case, I'm sure you'll be taken care of and come through any required surgery smiling and better than new.
But... have you been tested for sick sinus syndrome? My father has had fainting/sleeping spells and vertigo, and it turned out to be the sinus node in his heart. It regulates the electrical impulses and when not working properly, apparently these are the result. The solution is the implant of a defibrillator and pacemaker - outpatient surgery these days, with battery life of 10 - 15 years, so it's not like there's a lot of future maintenance involved. They're tiny, and can send their data over the phone - it's really amazing.
Can't wait to hear how you're doing and what the results are! All of our thoughts are with you!