Confused and unsure…

Mia

So had my first ultrasound on Monday going in thinking I was 8 weeks that day, as that’s how far along I should have been from the first day of my last period…. Yet the man doing the ultrasound said that from the measurements of the baby I was only 5 weeks and 4 days along… I was REALLY confused as I had blood tests done 3 weeks ago to test my HCG, and when I got my results back they were at 1038 which put me at 5 weeks… not sure how I’m only 5 and a half weeks when my blood test results said I was 5 weeks 3 weeks ago…. Not sure how to feel or what to think…. 😣