Hcg did not doubled as expected

Hi Mummies, it’s a trauma for me for the past few days. According to my period calculation, I should be on my 6th week. And went for a scan, no yolk sac or baby was found. Gynae suggested to take 2 blood test interval of 2days to check on hcg level. She mentioned should doubled up, but mine didn’t. It came back with 7100, I started off with 6226. She suspect baby stop growing or it’s an ectopic pregnancy. Anyone with same experience? I read online but not all articles shows that the hcg has to be doubled…