Taking someone else’s progesterone suppositories

So very long story short I’ve miscarried THREE TIMES! Every time I’ve miscarried I’ve went to several military doctors trying to get tests done to figure out what’s wrong. After my second one I asked for them to test my progesterone levels and instead they tested just about everything else and then I got pregnant again and lost it. I asked repeatedly for them to test my progesterone and they wouldn’t. So I went to the lab and requested it myself and finally got the test after some arguing. AND WOW I was right. My progesterone is LOWWWW. And I have an appointment Friday to see if they want to put me on progesterone which I don’t even know why that’s a question. If they don’t give it to me my sister in law has refills for herself she wants me to have. Should I take them? I honestly believe this is what’s best. All the other tests have came out FINE. Every ultrasound has come out FINE.