I got bitten by a tick and now I am on an antibiotic. How will I know that I did not get Lyme disease. Is therea test?

Lyme disease. Check out http://www.Cdc.Gov/lyme/ & http://www.Mayoclinic.Com/health/lyme-disease/ds00116 for info on lyme disease. Yes, there is lab testing available but we don't usually recommend it unless we're highly suspicious. You'll need to wait a few weeks to allow your body to develop antibodies against the bacteria in order for tests to turn positive.