I, like quite a few others, experienced pretty back motion sickness when I first started my lessons. The first 10 hours weren't pleasant! My instructor was amazing though and would spot the signs before I even started to feel much discomfort. As with most things though, the more you do it, the more used to it you become.
He recommended (and now I do) ginger sweets. I had "gin-gins" (can get them in health shops) which are a little sweeter than just raw ginger and they really settle the stomach.
Just don't kiss her after. They stink.