6 week ultrasound but baby measured 5 weeks?

I’m worried that there’s something wrong. I don’t understand why my baby was measuring smaller than what should be, going by my LMP.

I should be 6+1 going by my last period.

The doctors aren’t concerned, on my report it says that I’m a week earlier than 6weeks and it says “tiny echogenic structure within gestational sac. A yolk sac is not well seen at this time”

I’m so worried. I can’t stop thinking about it. I don’t want to lose this baby. I’m a stillbirth Mom, lost my last child before giving birth. This is just too much. Now I have to endure over a week of EXTRA anxiety because they made me go in for an early ultrasound. I wish I didn’t go, I wish it was scheduled at like 7/8 weeks like normal.

Any successful stories of babies measuring small before heartbeat is detected???