Progesterone Question

Ladies I just wanted to know your experiences with progesterone. We had a miscarriage in June and am currently 7 weeks pregnant. We saw the heartbeat at 5w5d however I've had more bleeding and cramps with this pregnancy than with the baby we lost. I begged my nurse to check my progesterone so they finally did today and it came back at a 4.7! Has anyone started progesterone this late into the first trimester and had a healthy baby? I'm just so scared that it's going to be too late.