My LMP was on Dec 1, 2013, my husband came back from abroad last Dec. 26, 2013. He stayed with me until Jan. 15, 2014. We had un protected sex and we also tried to conceive for that days. I never had my period during his stay, but now I have very small amount of light brown discharges since Jan.25 evening. I always have heavy menstruation every month but different dates since I was 12 yrs. old. My last hpt last Jan. 31, was negative. And yesterday i had brown discharge then real blood like menstruation. What causes spotting before my period? Thank You.