The severity of your Motion Sickness is a measure of your sensitivity threshold to small accelerations. The better the pilot the more sensitive he/she will be to the motions of a vehicle - be it a bicycle, a car or an aircraft. That better pilot will be amongst the first to become airsick if someone else is doing the manoeuvering. Rarely will that better pilot become airsick if he is doing the controlling himself. Spins are an exception but in a spin you are not in control.
Value your sensitivity to motions because your precise control of such motions when you are doing the controlling will be above average.