Depo shot-periods going on 3 weeks

Hannah
Hello all! I got the depo shot first day of my period and by the second day it was so light!! Normally I wear the thicker pads, I can now wear the thinnest liners ever and I'm
In heaven. Except one thing, this is going on three weeks I've had my period.. No pain, no headaches, pretty much just spotting, my normal periods lasted a week and were heavy. So this is a week longer than normal you could say. I read online and I saw posts saying if it's the normal heavy or heavier than normal to go to the doctors. Since its light and one pad can last my the whole day, I'm not too bothered, but is this normal?
Ps, this is my first injection of depo