Dating Scan incorrect

Hi

I had my early scan today. It’s seems to be iff by two weeks, it is saying that I’m eleven weeks. If this is accurate then I conceived whilst on my period.

My last period way 30 May 2019. Therefore I am 11 weeks from my LMP but I had sex two weeks after. My average cycle varies between 28-34 days. On average 30 days.

Please can anyone let me know if I should be worried that they have completely got my scan wrong ? How is it two week ahead ? I was expecting it to be a week or two less than the 11 weeks I should be today. Help please