Progesterone too low?

Hi everyone, please help ease my mind!

I just got more blood work back. The first day of my last period was August 28th, so that should put me at 6 weeks and 5 days. My HCG level is 12,035, which I think is pretty good. But my progesterone is 12.9. This seems a little low to me, especially considering that my doctor has me on progesterone vaginal suppositories. According to the chart on my lab results, it looks like it's on the low end of normal, but I'm still concerned that it's on the low end at all.

I'll attach a picture of my progesterone results and the chart. Can any of you tell me what your experience was and what your progesterone levels were around this time?