Depo shot and periods

Hey guys, I've read many times that when on the Depo shot you don't get a period because your ovaries are "resting" and your uterus lining doesn't grow and when you are off the shot you get your period back within 6-18 months

How ever,

I got the shot in september and early November I got a very light period and ever since my period has not fully went away, sometimes it's bright red and other times it's all dead blood with clots

Is this normal?