When to test?

Rosie
Hey ya'll! How soon should I test if my expected period is due in 8 days? My hubby and I DTD during my fertile window (9/30,10/1,10/4). I have a mild soreness on my boobs. I haven't gotten any spottings yet but I feel some mild cramping like I'm about to get my period. Not sure if this could also be a sign of pms.