I had unprotected sex on the 5th Dec, 4 days later I was so fatigued, body aches and cramps light pink spotting started which then continued still to today the 15th Dec but more brown in colour. Not enough to use a sanitary pad but it's there with each wipe and quite thick at times although more like discharge when I wipe. Have done pregnancy test its negative, but maybe it's too soon to take a pregnancy test? Not sure if this sounds like implantation bleeding or not? Not had a baby before. I have PCOS so periods are irregular. My last period was on the 17/11 so not due my period for another week. Period tracker app says I should have ovulated on the 6th dec so that's the next day after intercourse. Thanks.