Ultra sound

Lacy β€’ Mummy to two girlies 😍 πŸ‘©πŸ½πŸ‘ΆπŸΌ
So we went for our first US on Wednesday. I thought I was about 9 weeks but they said I'm only measuring 6 weeks and 5 days. We have to go back next week to see if baby and grown and I've just got my dates entirely wrong or it may be that baby had stopped growing at 6 weeks and 5 days and this will be a miscarriage. Trying to stay positive. Anyone have any advice or a similar situation with gestation dates? Thanks in advance guys πŸ’•