Can Depo Provera Cause Heavy Discharges?

Hello. Earlier in the year, I was on the pill, but switched to Depo Provera, due to unexplained bleeding for the 3 straight months I was on it. I received my first shot in last April, didn t get my cycle the entire month of May, however, this time last week, I noticed dark blood discharge. I have been discharging ever since. It s been fluctuating between red & black blood now, however, and is heavier, then light & so on. Should I go back to my doctor and discuss this issue?