5 weeks 2 days, only a sac, no yolk????

I had an ultrasound yesterday for some pain I was having, I was expecting to see at least a gestational and a yolk sac but there wasn't a yolk sac, just a gestational sac. A really tiny one. I should have been 5 weeks 1 day, and the tech said I could only be between 3-4 weeks because all there was was a sac, and the machine starts measuring at 5 weeks. So now I'm beyond worried that my baby isn't growing and I will miscarry again. I know I ovulated earlier than glow said so really I should be more like 6 weeks, I thought. But now I'm sure this baby isn't going to happen.