I agree that you should try spreading them out. I think if you do that, you might be able to pinpoint a specific med that makes you sick, or you'll be able to tell if all of them make you sick.

FWIW, I have a sensitive stomach too. I like to take one at a time, 30 mins apart. It's usually the lamictal that gets me, and I think it's because it's large. (Other large pills make me nauseous too, so I'm pretty sure that size is the problem for me.)