Pregnant with low hcg, on progesterone & started spotting today

Hi,

I got a faint positive on 12/29/2018 & did bhcg on 31st. It was 11. Doctor said its very low but I was 3 weeks & 4 days only. They called again after two days and bhcg was 16. Now, I have another blood test scheduled on Monday ie 1/7/2019. But, I started bleeding a little today. I don’t understand what’s happening I am 400mg progesterone still how can I get bleeding? Is it a bad sign? 😔