sex before "scheduled period"

My periods are usually regular (on the 15th) but last month my period came on the 11th and it was all normal. Now,  my boyfriend and I have been having unprotected sex since the 8th it's now the 12th and still no period. Now mind you I've had cramping around the 8th up until now thinking my period is going to start and it's not. No signs of blood just cramps and a little discharge. Now I know when I'm pregnant (Been there before) but this time I'm not sure. Could it be my period wanting to start ? Or could us having unprotected sex (Letting him cum in me 😩) have something to do with my period not being here. I know it's best to wait It out and see if it comes within the next week but I'm just very curious. Can you still get pregnant on the day before your scheduled period ?