Low Progesterone

I'm 6w2d and have been having blood work done every few days to make sure my HCG is rising normally. Everything was looking good, HCG was more than doubling. Then my doctor called and said my progesterone levels are very low. From what I understand, you cannot maintain a pregnancy without sufficient progesterone. I've started on a progesterone supplement (vaginal suppository) but I'm terrified I'm going to lose the baby. Anyone have experience with this or going through it now?