Baby growth on ultrasound?? Help

I went to the hospital due to bleeding. They did an ultrasound and everything looked great and heartbeat was good. I thought I was 9 weeks according to my period. But baby measured at 7 weeks 6 days. Went my Ob 3 days later and everything still looked great they said but the baby measured the same. They wasn’t worried but I kinda am. Is this normal? Has this happened to anyone else?

Also, bleeding as of today has stopped!! :)