My period was 7/1/13 with a 25 day cycle.  I had sex during ovulation week and I'm not due for my period again until 7/25/13.  I started with light pinkish bleeding (not spotting) but no where near my usual cycle flow on the 18th which is approx 9-10 days after dpo but a week before my period is due.  This morning my cramps and back pain were so intense.  I've felt pulling and pinching inside my lower abdomen for the past two days.  My legs even hurt.  I took a pregnancy test this morning and it was negative.  I'm going to test again in a few days.  Looking for someone's opinion????   This is killing me!!!!