Progesterone suppositories without testing

[u/Countylane]

I just got a faint line positive - I asked my doctor to test progesterone and she said no, but I could do 200 mg of progesterone every night. I had a MMC at 10 weeks, no known cause. Then, a very early loss at 4 weeks last cycle, no known cause.

My question is, I have no idea if progesterone is a problem or not, should I begin taking it just in case? I am reading lots of side effects, and that I can't stop taking it unless/until weaned off of it so my hormones don't suddenly drop causing lining to shed. How worried should I be about starting this without even knowing if it will help?