OMG sorry to hear. Same thing happened to me except I was cramping first and went to the ER and they did the ultrasound. Then the next morning it was when I finally had the miscarriage. If they cannot detect a heartbeat and the sac is empty, then you already miscarried. It just havnt came out yet. Same thing they told me. It really hurts to know but I hope the best for you. By the way, take some major pain meds like percocet and muscle relaxer and a motrin 800 combined. It wont kill you trust me, my doctor put me on flexiril, percocet, and motrin 800 and insisted I take them at the same time. It will ease the pain a lot a it will help with your uterus contracting. It also relaxes you and will help you sleep through it. Good Luck honey and sorry to hear that.
If you are suppose to be 9 weeks and the ultrasound is showing six weeks with only a sac no fetal pole and no heartbeat, and bleeding it sounds to me like a miscarriage. It could also be you aren't as far along as you thought you were. did you doctor schedule you for another ultrasound in a week? If they did that is good they can check and see if anything does show up, if it isn't a miscarriage. Goodluck.