I had vertigo caused by an allergy to wheat - the inflammation caused my inner ears to fill with fluid which disrupted my balance mechanism. I'd get the sensation of the whole world flipping or spinning around me, couldn't tell which way was up, and once it passed would come the sweating and nausea - a bit like seasickness.
Hmmmm....this is sounding veeeery familiar. While we've been eating 80% raw, I haven't been so strict about my gluten intake. I think this is probably the problem, and maybe the blood sugar levels too. Thanks for your replies.