Please help!

Good morning! So try and stick with me through this post…

I know for a fact that I was ovulating and conceived on April 24th. I got my first positive may 4th. The tests for darker and darker! I had what I thought was a period March 31st for like 2-3 days so that’s what I told the doctors my last period was. Well I went to an early ultrasound yesterday where they said I would be 7 weeks and soemthing and we only saw a gestational sac but it was empty and measuring at 6 weeks. I am devestated. But when I got home I remembered I got what was like another period on April 7th. I went back In texts to my husband and I texted him April 7th saying “my periods back, I’m so mad” so now I’m wondering if maybe I had the wrong period. They had me get blood work and I go Sunday again to see if it’s doubling. Yesterdays blood work came back at 24,807. I’m so hopeful it was just too early bc I was off on my period!! Any thoughts or similar experiences would be amazing!! Anyone not see a yolk sac at 6 weeks but a little later?! Thanks!!