worried.. PLEASE read and put in your input

Kelsey
---On January 24 i got my bfp! The same day I had blood work, HCG was at 229.. they saw nothing in the ultra sound.
---On January 31 my hcg was 3,647! On this same day, they were able to see a sac and yolk, still super small though!
---Today, on February 7, A FULL WEEK LATER.. they saw the same thing.. ONLY a sac and yolk.... I get the HCG results on Thursday...
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They gave me a due date of 9/14.. which can't be right if I'm only around 4-5 weeks..
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Is this normal?? They said I'm either around 5 weeks... or the pregnancy isn't progressing... has this happened to anyone and they went on to have a normal pregnancy? I'm freaking out 😔