My neighbors say my new doctor tends to overdiagnose everyone. He thinks I might have carsickness. Can you tell me the symptoms?

Nausea. A careful interview (history) will help your provider determine whether you have carsickness (motion sickness). It is more common in people with migraines. Symptoms can have varying degrees of intensity. Typically nausea and feeling poorly occur when the car is in motion. The more winding the road, the more intense the symptoms. Looking out towards something on the distant horizon seems to help.
Try mag and B-comple. Carsickness is a form of vertigo/disequilibrium. I've had much success with treating this with magnesium (up to 600mg twice daily--ask your doc first if you have kidney disease), and a b-complex vitamin. I'm always looking to find the root cause of symptoms (e., g. Vitamin deficiency) instead of band-aiding symptoms with prescription drugs. Give it a shot!