Progesterone Supplement Experiences?

I've been taking Prometrium 200 mg vaginally twice a day as per my RE's rec. We're doing it "just to be safe" because of my RPL.

I thought it would help me feel better about not symptom spotting during the 2WW, but I'm finding conflicting info on what are progesterone symptoms versus HCG. I know progesterone is MOST of the reason for PMS symptoms and early pregnancy anyway, but any experiences? I've read nausea is more HCG than progesterone, for example. Or I know sore breasts can be from prog, but what about sore/tingly nipples?

Honestly, I"m not sure you really can tell the difference. I've gotten tons of q's on this over the years and haven't been able to pick out any trends.

Hoping that someone with more experience than me chimes in.