I am 18 years old. Since I was about 15 I have had irregular periods, about 2-4 every year, each being 2-7 days long and farely light. My last period was july 3-14 and super heavy, with clots that were larger and thicker, about the size of a flattened cork for a wine bottle. It also lasted for 12 days. After my period ended I was spotting this light brown stuff for a few days. Now its eighteen days later and I m spotting the same light brown stuff. Also when my boyfriend and I had sex today I started to bleed. The bleeding went away, but the brown stuff is still there. The insides of my body have been hurting above my pelvic bone on the left and right side also, like a stabbing or pins and needles. And I m very tired all the time lately. I was just wondering if I should be worried.