Progesterone to prevent preterm labor...

I'm 23 weeks and 2 days and my doc has had me on vaginal progesterone pills since week 20 because my cervix dropped down to 2.5. They measured me again a few days ago and I'm down to 2.1. Planning to measure me again in another week and I'm scared if I've dropped again what will happen?? My doc has thrown out so many maybes. Like maybe I'll be hospitalized. Maybe I'll be put on bed rest. Anyone gone through this?