Low HCG and Progesterone, thoughts?

Background, I have had multiple miscarriages (had my last one in July at 7 weeks) I am working with a fertility clinic but they have been less any helpful on most things.

My last period was on August 8th

I found out I was pregnant on September 4th. Got blood work done. ( I have been spotting since the 7th)

9/7 4:11pm --- 13   progesterone 8.3

9/9  4:30pm --29  

9/10 9:05am--37

9/11 3:53pm--74  

9/13 9:15am--123 

Now my doctors say the numbers are low which I agree, even though they are doubling every 48 hours. My last pregnancy they were at lot higher. I am on a progesterone suppositories to rase my progesterone.

Has anyone gone through this and had a successful pregnancy?

I'm worried with how low the HCG is that it might not be a viable pregnancy. I would be crushed to have to go through another miscarriage.