Supposed to be 8 weeks 5 days vut ultrasound said differently?

Amy • Married and we have our rainbow baby strong and now a toddler and we have #2 due in august hope she is and wishing everyone a healthy pregnancy and delivery 💍💏🌈💗🤰

Is this normal. My HCG levels are basically setting me in the 8 week period but got ultrasound today and it's saying 6 weeks 2 days. Is this normal? I had a miscarriage back in April so I'm just super nervous