progesterone Suppository

Hi Ladies. So today I went in for blood work. I am 4 weeks and 4 days. My hcg was 678 but my progesterone level was only at 10.5 and my doc wanted to see it at at least 20. So she prescribed me progesterone suppositories, and I started tonight. I had a miscarriage about a year ago and I'm just really worried about all of this. Has anyone had experience with the progesterone suppositories or low progesterone levels? Thanks in advance!