Ladies please read long post

LMP was august 29th positive opk on September 10th and cramps and implantation bleeding to follow. At 4 weeks Went to the er with cramping early ultrasound saw sac and what they thought was a ectopic later ruled out. Hcg was 3,000Now on October 4th I was 5 weeks 3 days I had another ultrasound they said they they seen a sac and yock and a fetal pole with no heartbeat (which is right because I was only 5 weeks) they said the fetal pole they measured was 6 weeks 6 days? My Hcg was 22,000 so rising normally I just can't figure out how they measured the baby at 6 weeks and 6 days and a baby that old should have a heartbeat my period was very regular I'm sure I got pregnant September 12th I started pregnancy testing very early first very very positive was at 6dpo. What do you ladies think? Here are my results sorry about the long post!