honestly not always does that happen. but be mind that having inprotected sex and having your partner ejactulate while doing so is possible. it's not a myth that after a woman has her period that when she starts a new ovulatuion cycle that she is most fertile. it is actually proven and suggested if a couple wants a child that its the way to go about it. i would suggest getting a pregnacy test a day before or after you next missed( if it is missed) period.
we had sex the day after my period is it possible to be pregnant?