O. - I am so very, very sorry for your loss. It's really your choice about what you do and it may come down to just an emotional decision. I've had more than my share of miscarriages and all of them "feel" the same as they come on - just like a period of sorts, only a lot more cramping. You will know when you pass the pregnancy, as it will be a lot of mucusy looking globs intertwined with blood (sorry to be graphic) if possible, try to save it as your doctor may want to run tests. It is possible to have a few days of bleeding or spotting prior to this, and then you could have bleeding off and on for a few days after. But trust me, you'll know. You won't be able to keep yourself from looking for it. Don't wear a tampon, wear pads.
One time I had miscarriage that spontaneously aborted, and I elected not to have a D&C and pregnancy tissue continued to grow, causing me a lot of issues and heartache. So to that end, I, personally, think it's a good idea to have a D&C after your body passes the pregnancy.
Miscarrying is tough - please make sure you talk to your doctor about the emotional impact and if you are so inclined, don't hesitate to ask for some medications to help you through.
You will be in my thoughts and prayers as you go through this difficult time. Please don't hesitate to contact me if you need to. Good luck - S.