Last period was May 25th to May 28th. We had sex on and off throughout my fertile week. AF is due this Friday and I started light spotting (only when I wipe) and it has EWCM too. I've never spotted before a period before. Plus I have light cramps in abdomen and back (which is normal for AF). We suffered a loss back in March so my cycle was off, May was a normal period though. Could this be implantation bleeding? When is the soonest I should test?