Im sorry for your loss love..I had 3mc and I was on for a month after but they gave me anti-biotic witch sorted it and another time I got given some tablets to correct it they both helped I'd go see your doctor they can help you love x
You may want to call, not to be graphic but they may not have gotten everything. With my first m/c that happened to me and i had to go back 3 weeks later for another d&c. Good luck.
Sorry for your loss! I've had two miscarriages myself, and the first one I bled for 30 days, my doctor told me it was normal but if you feel concerned or worried I would go get checked out to make sure everything is ok. :)
Call your doctor, 20 days is a bit long. Sorry for your loss