Hcg numbers are low

Cassie • Currently pregnant and I have an amazing 9 year old daughter!!!
So I finally got a positive and I'm pregnant, well at first my Hcg was at 50 then 300 now at 400. So my doctor is saying that's not a good sign and my numbers should double. Anyone else experience this? I should be 4-5 weeks and he is saying that it should be around 1400 ugh I'm so stressed. Any advice😞?