I was due to start my period Jan 10th, well on jan 6th i started getting brown discharge and assuming it was my period i put a tampon in and went on with my shift. Well 5 hours later when I got off work I took ti out and there was a very light brown spot on it but was very clean. The brown discharge continued for three day and then stopped. My period never showed up and still isnt here. I have taking two pregnancy tests, but both we -ives. I am now experiencing back pain in the lower left side, and also cramping occasionally. What could this be?