Dates on scan would generally be expected to agree with last menstrual period but that's only if we all had 28 day cycles and ovulated on exactly day 14 which is not the case so just because the dates don't agree doesn't necessarily mean the pregnancy won't continue. Did they not book a second rescan to be sure? In our unit we would class this as a 'pregnancy of uncertain viability' and book a rescan in 10-14 days to see if the pregnancy has progressed
Went for my follow up scan today and now even more confused. The lady that scanned me today said that in the last scan they couldn't see the baby, only an empty sac, which only measured 6 weeks, where my dates said I should be 8 weeks.
Well today they scanned me and said that this time they could see the baby, but it was measuring at 5weeks 4 days. They said it didn't have a heart beat but they wouldn't expect to see it yet. They said the sac was still measuring 6 weeks.
I now have to wait another week as they said there has been development from the last scan and they wouldn't want to start anything in case it was a viable pregnancy.
I've been in almost exactly the same situation as you. My follow up scan showed growth / progress but not as much as should be expected. For me it did not end well (sadly) but there are lots of women out there who have had happy endings in this kind of situation. Early pregnancy is very hard to measure or assess with an ultrasound.