Low progesterone, 6 weeks 4 days

I went to the doctor yesterday and we only saw the yolk sac. I go again next Wednesday. But they ran blood levels and called me today and said my progesterone is at a 4.27. I ovulated on CD 17 or CD18. So my doctor originally thought I am earlier than what they thought based off my LMP.

I know nothing about this but my doctor prescribed me suppository medicine and said I have a chance of miscarrying. I am so worried. I didn’t have this problem with my first son.

What can happen? What are risks? Is there anything I can do besides take that medicine? Can anyone please share their experiences with low progesterone?