progesterone to prevent miscarriage

Asia • Mommy to a boy 💙 baby #2 due feb ‘18.💗 happily married 😍
Has anyone ever bought progesterone supplements without a doctors prescription? I just found I'm pregnant, I'm early and since I've had 2 miscarriages about 8 months ago I want to get started early as possible. I looked up the symptoms for low progesterone and I'm pretty much having all of them. So has anyone ever taken progesterone supplements to prevent a miscarriage with or without a doctors prescription? Also  If you've taken it with a prescription how far along in your pregnancy were you when you started it ?