Only small sac on u/s at 5w6d.

Crystal

Has anyone else had this happen? I was hoping to see a tiny something in there, but just the sac. She said the sac is still measuring too small for there to be a fetal pole yet and I am to go back in 10 days for another scan. Should I be concerned about a blighted ovum yet? She said the size was on track for 5-6 weeks.