No baby

Should i be worried that i didn’t see my baby on US nurse said i was measuring at 6 weeks there was a yolk sac but no baby she said it was still early but i read most of y’alls stories and y’all seen Baby at like 5 weeks i know every woman is different next US is in two weeks

My last HCG level was 4323

Miscarriage on April 16 at 6 weeks