Ultrasound at 5 weeks 4 days

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Hi ladies, 
I had an ultrasound yesterday and all that showed up was the sac. No embryo. My dr. said this is normal this early but I thought with my last pregnancy I was able to see the baby. He moved my due date from the 11th to the 14th. I also go back in 2 weeks for another ultrasound. Any one else have this happen?! I'm pretty worried :/