BUT sperm can live in you for up to 5 days if the environment is right. Meaning if you had sex on day five of your cycle then there is a possibility (a small one) that there is sperm in your vagina/uterus on day 10 of your cycle (if you are having unprotected sex). The chances of you ovulating on day 10 of your cycle is still pretty small but it is possible.
Highly unlikely because women don't normally ovulate that close to the start of their periods.
not likely for you to get pregnant on your period, however theres always a chance unless your using birth control and condoms