If there's no heartbeat and you are measuring behind, it is most likely a miscarriage. I would wait a week and ask for a repeat ultrasound JUST to be absolutely sure. It IS possible to have a missed miscarriage which simply means that your body has not recognized that you have miscarried and therefore has not begun the process of expelling everything yet. This happened with my first miscarriage. I'm sorry :(
i went through the same thing in may. i was expecting twins and at 10 wks i went in for a us and no heartbeat. so i was told to try to let them come out on their own, but it took two weeks for tjat, and i didnt pass everything so i had to have a D & C. im really sorry. its such an emotional issue. best of luck hun.
I have read that one can wait for a week to let nature take its course before attempting D& C ...but I am no expert