If i had unprotected sex 3 days before my period will i going to be pregnant?

Pregnancy has been documented from exposure during any day of a woman's cycle including during menses but such events are rare. When/if cycles are very irregular ovulation at odd times can occur & increase that possibility. When someone has predictable cycles, mid cycle ovulation is expected & chances of pregnancy near menses is minimal. Mid cycle sex is more likely to make a baby.