Worried about growth of baby

Frances

Based on my ovulation date I am just over 5 weeks with a due date of Sept. 7. But I just had an ultrasound today and it showed the sac as being 4 weeks and a due date of September 15?? Is this a bad sign? We've been trying to get pregnant for over two years, I really want this baby to stick...

Has anyone else had experiences with this? My doctor told me to come back in two weeks.