Early ultrasound

I went in today for an ultrasound because based on my last period I would be 6weeks 6 days. I knew I wouldn’t be that far along but I thought maybe almost 5 weeks. They were only able to see a small gestational sack but no baby yet and she said too small to really get a date measurement yet. I’m hoping maybe I just ovulated really late. I get beta hcg tests tomorrow to make sure levels are rising. I know I went thru something similar with my second but it’s still nerve wracking. Also she said my uterus is retroverted so that makes early ultrasounds harder too.