I normally get my period every two weeks; light, lasts 3-4 days. I had sex on April 14th and got my period within an hour or so after intercourse (it was technically already 4 days late, but no chance of being pregnant then). It ended the next morning, but now I have a slimy reddish, but mostly brown discharge (seems to be only when I wipe). I have had pain on my right side (under hip area) since the day after sex. What could it be??