Katie Scarlett has gotten car sick twice since we got her and both times I was holding her. When we put her in her Snoozer carseat, it was like a light went on for her...she never gets sick anymore. I think she just feels better in her carseat and doesn't feel the motion of the car as much. I was going to take all the advice that I read/heard on YT about taking her for short drives everyday, but once we got her carseat, our first drive was over 2 hours and she did fine. She now loves the car and knows if I get out her harness we are going on a ride. It has been our lifesaver. Sorry I could'nt give you more advice, but I'm a newbie to Yorkie mommyhood and this has just been my experience.
I hope you guys can get over the car sickness. Poor little thing! Hugs going out to you guys!