Your vet can supply you with a medication for car sickness. Especially for long rides
My Scottish terrier takes a natural supplement called Valerian root. You can buy it at any place that sells natural herbs.
He is 14lbs and we give him a full capsule. You can open it and sprinkle a little on his food. It helps decrease the anxiety and calms them down naturally. It smells awful...but the dogs love it!!!
My daughter will take one if she can't sleep.
She says it relaxes her...not necessarliy making her sleep.