Low progesterone worry

Hello!

I am 8 weeks pregnant, and I was just told that my progesterone levels are low and I must take a supplement via vaginal insert until at least 12 weeks. My level was at at 10, and my doctor said I should ideally be at 15-20. I go next week for another blood test and ultra sound. This is my second pregnancy, and I never experienced this with my first. I still breastfeed my 19 month old once a day, and it took me 13 months to get my period back. I am terrified of the idea of miscarriage, and while the doctor didn’t seem worried, I am FREAKING out. I went last week and baby had a strong heartbeat. Should I be very worried? Has anyone gone on the supplement and went to have a full term pregnancy? Looking for some positive reinforcement. Thank you! ❤️