7 week scan and no baby...

I had a scan at what I thought was 5 weeks and they saw a sac then at 7 weeks they saw only a sac and a yoksac. They were thinking they should have seen the baby. The ultrasound tech said she was thinking it was just not as far along as I thought. The doctor however told me I would have a miscarriage. The doctor later called back and said she might be wrong and just hold tight. Any positive vibes are greatly appreciated.

I am lucky enough to have a healthy 20 month old but would love to be adding to our family😔

Also, I was tracking my period and conception dates pretty closely so I am really thinking I’m about 7 weeks.