Sorry for the delay. I just saw your question just now. Did you have sex any other day but that day? All women are different about fertility, etc. My daughter seemed to have gotten pregnant during her period if that is possible. If you would like to join a support group, please join at http://groups.yahoo.com/group/unplanned_pregnancy_help/
Hope you are ok and please feel free to let us know on here what happens or email me at DCHERYL51@yahoo.com so we can talk more.