While there is always a chance you could be pregnant, it is not likely. The reason is that most woman don't ovulate immediately before or after their periods, but rather about 14 days after the first day of your period. If you use a calendar to track your periods, which you should, you can look at the date you started your last period, count fourteen days and that is around when you were ovulating. If this even didn't occur on the 13/14/15 day after the start of your last period, it is very unlikely you are pregnant.
However, your cycle is your own, and just because this is true for most woman, doeesn't mean that you don't ovulate earlier or later. Just to be on the safe side, don't drink or smoke or do anything else that is problematic!
Good luck!
