Gestational days advice pls

Hi, not too worry about it! Sometimes it’s also your baby curling up. I went ytd for a urgent scan cause I had some abnormal discharge, my baby was measure at 2.78cm which is 9 weeks 4 days. Today at my regular appt, my baby was measured at 2.76cm. Haha. So still 9 weeks 4 days today. Ytd baby was moving a lot and stretching, so doc says it’s normal that at the moment they stop the scan to take a picture, the baby may have moved and a shorten length would change the estimated date and CRL of baby.