Is D&C Required In Case Of Miscarriage?

Hi, I was 6 weeks 5 days pregnant (from my LMP) when I started bleeding. 5 days of bleeding later I had an ultrasound which confirmed that I'd had a miscarriage. My hcg levels had also dropped to 400. The bleeding was only heavy (about as heavy as the first day of a period) for the first 2-3 days, and it was also only then when my pelvic area felt moderately crampy. The cramps disappeared over the next few days, and the bleeding slowed down - am only needing 2 or 3 panty liners (not pads) per day. However, it is now 20 days since the bleeding started, and it hasn't stopped. It has fluctuated and I've thought it was stopping but then it comes back in a few hours. It hasn't been heavy apart from the first 2-3 days, and I have no other symptoms. I've been seeing my doctor, who tested my iron levels 12 days after my bleeding started (fine), and I told her then that the bleeding was stopping as I thought it was. She said to go back if there was still bleeding after a few days, but I haven't gone back because it's so light and there are no other symptoms. The ultrasound showed that my uterus was clear. I really don't want to have to have a D&C. What are the chances that the bleeding will just stop naturally like it should any day now and I won't have to worry about it? Thanks for your time, Wanda.