So confused - early or blighted ovum ?

Hi everyone, I found out I had a miscarriage august 14th… bled for a week and then 2 weeks later august 31st/September 1st I got a posting ovulation but wasn’t sure since pregnancy tests were still slightly positive… we did it over the course of the next 2 weeks, fast forward today I am pregnant and ultrasound saw sac and yolk sac but no baby…. Sac measured 6 weeks 4 days.. doctor said that was normal and I was prob early?? Shouldn’t I be around 6 weeks?? Any stories would be appreciated!!