Miscarriage Questions

Danielle • Mom of 3👼🏻 engaged to my best friend

For those unfortunate ladies out there who have had a miscarriage, is the day you find out you are miscarrying the baby the weeks pregnant you are when miscarried or what the doctor says the baby is only measuring at? Because it was almost 3 weeks from when the baby stopped developing from when I found out via bleeding. Can’t really find any info on the internet. Any advice would help!