Gosh, it is interesting to see how many of us GNetters suffer from labyrinthitis. I had a sudden and terrifying attack about 5 years ago. Mercifully I was at home. I too thought I had had a stroke as the headache was worse than anything I had ever had and lying flat wasn't quite horizontal enough. Fortunately, although nauseous, I wasn't sick.
I took stemetil for a couple of weeks, and always have it to hand when the warning symptoms show - headache and uneasiness.
I shave always suffered from travel sickness, so try to travel at the front of coaches, facing the engine in trains, etc., and always take a pill before any lengthy journey.
It does go away, but my doctor told me it could last 3 days, 3 weeks, 3 months; his voice tailed off. It seems to be permanent.
the tinnitus I have is probably not associated, but can be very noisy indeed.
Good luck.