Hi, I ve been on birth control (microg.estin 1/20) for a month and a half now. Two days ago I started gettting really bad cramps/ back pain like I was going to start my period.. but instead got a really dark brown, mucusy like discharge . I m one week away from finishing my current birth control pack. What could this be?? Should I be concerned? I am sexually active and also purposely skipped my period last month with my doctors permission.