I need opinions, please!

Kimberlee • Mama x3 | 30 | Married ❤️
I want yalls opinions..... I had an ultrasound on 2/29 due to bleeding. Everything looked perfect, saw the heart beating. But when I went to consult with the doctor, she said I'm measuring small for 6 weeks (6w as of lmp) I know I ovulated on 2/1, so I don't know..... What did yalls ultrasound pics look like at 6w? I'm just confused why she said this. I'm freaking myself out.