Motion sickness happens when the movement that you see around you does not match what the vestibular senses perceive. Your brain takes in information about where you are (through your eyes) and how you are moving (through your inner ear). Your brain gets updates from both and integrates them. Having a mismatch of information, your brain fails to update which leads to confusion, then after nausea.
The nausea, disorientation and fatigue that can be induced by head motion. The first sign is usually pallor (a pale appearance). Yawning, restlessness and a cold sweat forming on the upper lip or forehead