Well I'm on Progesterone Supositories

This is my 6th pregnancy and I've never given birth, yesterday my OBGYN nurse called and said my progesterone level was a 9 and the doctor was concerned because they want It to be at 20 so now I'm on Progesterone suppositories every night until I'm 12 weeks! I'm happy but nervous because I've never carried past 8 weeks and I'm 7 weeks and 5 days, the thought of actually giving birth is scary because I was told it was never a possibility!! Has anyone had success stories,with progesterone or know how I'm feeling?