I agree, the doctors would have run tests inclusive of stool sample and blood work. They can find organisms in both that would determine whether or not she had food poisoning. The doctors wouldn't have told her that she's not contagious if they weren't sure. That being said, her being in your car with you, kissing you and touching you can't give you a virus. You have to ingest the virus which you didn't. Sounds like she is on the mend and that this will be a faint memory very soon. Try to find something else to focus on today. Start a project or hang out with new friends, this is honestly a waste of time to think about as nothing is going to come from it and you'll wish you had these hours and days back. You are fine!