8 weeks US no baby in sac?!

So a little back story...

I had an ultrasound done at my primary physicians office when I was about 6 weeks. The gestational sac was there but was not able to see the baby, they said it was too early to see anything and didn’t seem concerned at all.

3 weeks later....Today I went to the on/gyn to establish the pregnancy and the same thing happened. The sac was there but no baby seen. I should be around 8 weeks and worried that you should be able to see something by now!! Doc said the dates may be off due to having irregular periods. My blood was taken today and will be taken again on Tuesday to check hcg and another ultrasound on Thursday.

Also now that I’m worried about it, I’ve realized that my pregnancy symptoms have kinda gone away. No more bloating, not as tired as I was, not constipated, boobs still a little sore. My last symptoms that I remember were 4 days ago.

Help!! Has this happened to anybody else?