6 weeks but measuring 5 weeks

Nicole

Hi ladies, I just went for my first ultrasound today, and I was thinking I was 6 weeks and 3 days based on my LMP. I know that I conceived on August 15, and I was scheduled to ovulate on the 18. Today we only saw a gestational sac that measured 5 weeks. Could this be normal, or am I possibly having a blighted ovum/miscarriage? So worried, and my next ultrasound isn’t for another 2 weeks.