I'm sorry you're experiencing this! I was confused from your post - do you say your baby still has a heartbeat or not? I'm guessing no but I wasn't clear from your post. If the baby still has a heartbeat, I might consider seeing someone else to ask for a second opinion.
The later the loss, the more likely it is that the tissue will not completely pass on its own and will necessitate a d&c. You can talk to your doctor about how long they'll give you. It can take quite a few weeks for some people, and some doctors are not comfortable waiting that long because of the risk of infection developing.
Best wishes to you!