What are your experiences with this?!

Here are the dates and Hcg levels of this pregnancy starting at 9 dpo (10/24/18):

10/24: 8

10/26: 36

10/29: 212

10/31: 608

11/9: 10,658

11/11: 11,580

11/12: 5 weeks 6 days pregnant with fetal heartbeat 103.

Numbers were rising well and suddenly have almost plateaued. No spotting or cramping and u/s rules out an ectopic pregnancy and shows that there is an almost 6 week fetus with heartbeat where they said it should be for this stage (between 90-110bpm from 6-7 weeks is what they look for). Doctor says that sadly no viable pregnancy comes from Hcg levels that only rise 8% in 48 hours this early in the pregnancy.