I had sex on my period so if i already ovuated could i be pregnant?

Low risk time: If you were truly on your period and not around the time of ovulation then pregnancy is low risk. Timing intercourse around menstrual cycles and ovulation has a very high failure rate. Use over the counter Plan B if intercourse was within 72 hours to decrease the risk of unplanned pregnancy. Start birth control and use condoms to avoid these scares in the future.