I had my first ultrasound this morning. Today I am 5 weeks and 3 days pregnant. My appointment this morning was with my OB. It was a surprise ultrasound. She said everything looks good for where we are. However, I am feeling worried. This picture she gave me shows that the sac measured at 5.5mm. Does that seem correct? It seems a little small, but I don’t know much about this part as I have never made it this far. What were your sizes at certain times?