Maybe it wasn’t entirely the car ride, but a mixture of that and the stress of leaving her Mom? I would keep taking her in the car though, with the hopes she will get used to it. Ginger doesn’t mind the car at all—never has…it’s like she’s unaware she’s even in a car.
Some people say animals are afraid of cars because of a bad experience they’ve had in one. So maybe she’s associating the car with when her breeder took her to the vet? I don’t know, good luck though.