is all hope lost? (missed miscarriage)

Jessica
I was told this week that I likely had a blighted ovum. My HCG levels went from 5200 to 5800 (might have been 52,000 to 58,000 honestly don't remember) so they didn't double but they did go up over 48 hours. 
The ultrasound showed a sac but not embryo and we though I was 8w3d but looking by OD instead of LMP I was about 6w exactly. I am going in for another ultrasound tomorrow to confirm. I still have morning sickness, sore breasts, etc and no bleeding or cramping at all. Does it seem like there's any chance they're wrong or is it likely the pregnancy is going to end? Has anyone had comeback from numbers like that?