if your date to be considered, you should have at least 3 regular cycles before conception.
normally on 9 th week fetal pole
should be seen.
absence of fetal pole and gestational sac
with irregular margins indicates blighted ovum
But don't worry you undergo scan once again now to find out the present position, depending on that you can proceed further.
Discuss with your doctor what may be the cause for it and try to avoid in future.