Lighter than usual period

Usually I have a heavy period for three days then the last two are light. This time I was heavy only two days then the last three days I barely had anything at all. I'm kinda freaked out because during my fertile week me and my fiance were messing around and I gave him a blow job after my fiance had ejaculated he then put his penis in his pants then fingered me. Is there a chance he had semen on his hand enough to cause pregnancy and that's why my period was lighter? Am I over thinking the whole situation? I just know us getting pregnant before the wedding would embarrass his whole family.