Correlation does not equal causation. You do not know what the guy had, nor do you know what you have. Nor do you know if he is the one who passed it to you. You could have gotten it from anyone and anything you touched. You assuming it was this guy reeks of witch hunt and ignorance, not cool.
The swab is to test for influenza A/B - virus' infections. The swab does not test for bacteria, fungi or idiopathic causes of rhinitis/pharyngitis/gastroenteritis.
http://www.cdc.gov/flu/professionals...s/rapidlab.htm
Taking someone else's meds is always a bad idea. Interactions, expiration dates, etc etc. Seriously, you're gambling with your health doing what you did. Amoxicillin is an AB penicillin that also works on G neg staphs - will not work vs a virus infection. Again, correlation and causation: you don't know what you had, you don't know if the Amoxicillin worked on what you had. You need an AB resistance test on the specific bacteria to know. What you ARE doing is making room for the bacteria that are resistant to Amoxicillin on your body surface - Selection pressure. This is the chief reason we have MR bacteria - misuse of antibiotics. Get a prescription from a physician on a case by case basis - don't play chance with your health or anyone else's for that matter.
Get tested with a different test than the flu swab if you suspect you might have an infection other than influenza virus. Seriously. This is a no-brainer to any physician