9 weeks but measuring 6 weeks 😕

I’m very nervous to say the least! My first pregnancy resulted in my 12 week check up no heart beat and baby stopped growing at 8 weeks which resulted in a missed miscarriage. This 3rd pregnancy I should be 9 weeks due to my LMP but I did have my period twice that month and I used the tracker to track my ovulation. Dr is unsure whether viable or not so I will be going in, in two weeks for another ultra sound I opted out of the HCG blood drawing as I want to wait it out..Any other similar stories?