I threw up over my FI for my first full lesson, great way to start a relationship.
The cause was though performing "secondary effects of controls" each resulting in a spiral dive. This was repeated six times. Then a jolt up following by a jolt down though setting the trim totally out. Throw in some turbulent mixing with the ground on a gusty late Autumn day and I felt quite ill... The bags had been forgotten and we almost made it until we had to go around on short final. My body just gave up there and then.
Too warm clothing also didn't help. My tip as a Master Chunder, epxnading on 18greens's comment, would be to make sure you are cool enough but not freezing. I wouldn't be surprised if the additional stress of learning to fly puts your body temperature up.
Ultimatley it was combatted by continution of learning so more control coudl be taken away from the instructor. The body imo combats vestibular effects better when it can knows and can anticipate events.