Hi, I have no helpful advice, other than I also get mild vertigo even at depth, sometimes with no particular cause. You should go see an ear doctor recommended by DAN or another dive-knowledgeable referral service. The one I went to advised being physically prepared for dives, and taking it easy while on them. Lots of rest and hydration, good aerobic fitness, no alcohol 24 hours beforehand, and just taking the dive really really slow. I have a lot of trouble equalizing, even down as far as 10m, and my ears almost never equalize together. So maybe I am especially prone to it for that reason. One thing I do, is if I have a choice between going around an obstacle, and going over it, I always go around. That way I maintain the same depth, rather than changing depth and risking vertigo. (Of course, you have to re-establish your heading after going around.) I guess the only advice I have is to stick close to your buddy so you can grab on, and keep your eyes open! Keeping them closed will only make it worse.