Hcg still rising?

Hi all,

Hoping someone has some insight. At 6 weeks I saw a sac, yolk sac and fetal pole. I went back at week 7 and the yolk sac and fetal pole were gone (he tested my HcG and it was 13,000). Today I went back, since I still have no bled and my HcG is 30,000. They are sending me to get a high tech US. The nurse said it could just be the sac still omitting HcG or he missed something on the last US

I do not want to get excited like there is a chance my fetus is still alive because it seems unlikely.

Does anyone have insight or a similar story?

Thanks