You don't need a D&C right away, but it can't be left indefinitely if you have not passed the tissue. After so long infection can start to set in which can damage your fertility as well as your health. Give it 2-3 weeks and see what happens, and if you don't then I'd start talking to your doctor.
Until your hCG levels drop completely you'll continue to feel pregnant. It's an awful situation to be in, and a hard one. I'm sorry you're dealing with this, and I hope everything goes good for you. If you have any other questions, please do not hesitate to ask.
Your body knows the best listen to what your body says and if it doesn't happen with in a week or so naturally I would def talk to your doctor for a d and c because you can go septic if you body does not pass it.
You can wait as long as you want. You can choose to let it happen naturally. because you are so early, it shouldn't be too painful. I had 2 early m/c (5 wks and 6wks) and they weren't physically painful, just some moderate cramping and heavy bleeding for several days.
I also had a missed m/c @ 12 wks and was "forced" into a d&c. I was told at that point in time it would be like "going into labor" to let it happen naturally. To be honest, the d&c wasn't bad, I just did not like not being given a choice. It is really up to you what you wanna do; don't let your doc talk you into anything. Of course they will tell you that if you go naturally, everything may not come out adn you may end up needing a d&canyway. But I think those odds are pretty low. Anyway I am very sorry for your loss. Hope everything goes okay for you.