Vertigo can hit suddenly and last for however long and then wait to occur again whenever it feels like it. I'd never had any kind of problem until last May when I woke up feeling okay, went to the bathroom, and nearly passed out. I was sitting there thinking "huh...did I just about pass out???" I ignored it and went back to bed...woke up to the room spinning. I called my mom and told her I needed to go to the hospital. The only reason I got stuck in the hospital for 3 days is b/c my initial CT scan showed what looked like a blood clot at the base of my skull. They wanted to keep me until they were absolutely sure it wasn't a clot and the neurologist had had a chance to thoroughly check me out. Google "Epley Manuever"...it's an at home remedy that helps realign the crystals in your ears (which is what causes Vertigo). It made me really dizzy the first time I did it, but it really did help after that.