Progesterone question!

Hailey • Kinley Sophia was born in July 2015 and Theos Aiden born January 2017
I had a miscarriage before I had my daughter and the doctors said it was because I had low progesterone levels and I needed to be on the progesterone pills. I am pregnant again, I just found out and my appointment it in a week. Do you have to be on progesterone each pregnancy? I'm worried a week will be too late but that's the soonest I can go in