Now I'm stressing!

Jessica
I went for a dating scan today and they dated me at 5 weeks 3 day's. According to my calculations I was 6 weeks 1 day today. I got a positive ovulation test on July 8th and I got my first BFP on July 17th so shouldn't I be further along 😯 I'm so scared and nervous! Has this happened to anyone?? Please share!?