Flicker of heart beat but unmeasurable 6w3d

Jessica • 26th cycle TTC

Hey y’all. I’m 6 weeks and 3 days via IVF (so we know dates are accurate). I had an ultrasound this morning done by my doctor where we could very clearly see embryo/the “flicker” of heart beat but she couldn’t measure it. She tried and I guess just couldn’t get it. I’ve gone off the deep end googling and now I’m worried it should’ve been measurable. Any thoughts/experiences are welcomed!