You sure i can't get pregnant having unprotected sex 6 days before ovulation? i had sex at 1:30 pm and my fertile days are 08/24-29

Sure you can: Cycle timing has an incredibly high failure rate which is why couples start birth control. Six days prior to your period is a less likely time to get pregnant technically but not always reliably. If avoiding pregnancy is important to you please see your doctor to discuss more effective birth control methods.

Not impossible: Anytime you have unprotected sex and are fertile, you are at risk for pregnancy. Although 6 days before ovulation date is unlikely to cause pregnancy, it is still possible. You can guess when you ovulate but never know for sure, thus the possibility is there. That's why we always recommend "protection" if pregnancy is not desired.