5 weeks and no yolk sac.

So I thought I was 5 weeks well based on my ultrasound yesterday that I had due to some spotting which turned out to be a small subchorionic hemorrhage. my sac was measuring 5 weeks 3 days they didn’t see a yolk sac yet they didn’t seem concerned considering 2 days prior they couldn’t even see a sac and my numbers more than doubled but I couldn’t help but research it and then google got the best of me now I’m worried it’s not good that they didn’t see a yolk sac yet. So my question is have any of you ever not seen a yolk sac at 5 weeks?