One last period but pregnant?

Hello - anyone experience one last period before becoming pregnant... meaning... it is possible I could be pregnant... had sex on Oct 24, 25 and 29. And just got my period yesterday which was early for me. (28 days when I’m usually 33-38 days). I have pcos so things are always screwy with my cycle. I feel different with this period - bad headaches, upset stomach, fatigue. I’m wondering when I can test... wait until after this period is over? Thanks in advance.