Early Ultrasound?

Nikki👼🏻👧🏻👦🏼👼🏻👼🏻👼🏻👼🏻👼🏻

I am only 4 weeks and 2 days and I had my blood draw today which said my hcg was at 550. I was told those are good numbers. But then she called and told me that the doctor wants me to come in next Friday for an ultrasound. This had me very concerned why they would want me in for an early ultrasound? Someone ease my mind😔