I ve been on the Depo now for 11 yrs. And have never had any problems, last week i started spotting, red blood as well as dark, almost black mucus type discharge , My doctor had a pelvic ultrasound ordered and found nothing. I bled for 4 days, then stopped as fast as it started, Now i started bleeding again Saturday. I will be making a appt tomorrow with my doctor. But any suggestions as to why this may be happening after 11yrs?