Girls, can you please help me? I was at the doctor today and had an ul…

Girls, can you please help me? I was at the doctor today and had an ultrasound to confirm my pregnancy. My last period was June 19-22. On the ultrasound they saw a fetal egg 6mm/the body 3.7mm. She didn't see an embryo... But according to my cycle it should be 6 weeks... She said that the pregnancy is up to 5 weeks. Has anyone experienced this?