I had protected sex during my peak ovulation time aug 30, and then 12 days later got a period that was heavier than normal, can i still be pregnant?

Check and see!: Anytime vaginal bleeding is abnormal, in length, symptoms, or timing, check a pg test to be sure (if you are sexually active and have not had surgical sterilization). Repeat in a week & if negative, & you miss another period, see your doc to find out why. Follow the instructions on the kit, & be sure it has not expired, too. Also, infections can occur, if you are at risk of pregnancy. See MD.