I read that when you go and get your first appointment, your edd could be within a week or so based off your last period. It's possible. But it could also not be a good thing too, I had issue like this with my first pregnancy and I mc'd. I dont want to scare you, but you really never know.
At my first ultrasound all that could be seen was a gestational sac and I went on to have a successful pregnancy. However, as the ladies said, my story really has no bearing on yours and only time will tell for sure. Sorry for your previous loss and I hope that this will be your rainbow.
You could still be off on the dates. Hopefully next appontment will show more development. We had the same thing happened to us. Followed up a week later and same empty sac. They called it a blighted ovum. Fertilization occured but no baby ever formed. We were given the oprion of d and c or wait for nature. We waited hoping things would change but they didnt. I naturally miscarried around 10 weeks. The waiting was the hardest part because it was a constant state of limbo. The only thing that made the loss semi bearable was that there as never a baby and never a heartbeat. I hope it works out better for you.
Re: 6 weeks and 3 days - baby measuring 4 weeks 5 days no yolk sac
edited for spelling