You might want to do a pregnancy check? Otherwise, I don't think biking would intensify motion sickness in cars - it may just be that you have not been in a car in a while & are not used to it? There is a pressure point in your wrist, called the P-3, which, if you put pressure on when you feel sick, will releive the feeling. You can purchase wrist bands that you wrap around your wrist - they have a bean in them which you situate over the P-3 point to apply consistent pressure (you can make one yourself for WAY less than they sell these things for!).