Nervous for delivery ?

Hey mamas! im 270 pounds & 22 weeks! Honestly i think about delivery every day.. im so worried. I just dont have the breathe to push and im only going to get bigger. Please tell me ill be able to do it.. i dont know why im so nervous about it & im not even close. My doctor told me to walk to make it easier and i do but i still feel like i get out of breathe so fast idk how im going to push a baby out. any one else had this fear and ended up being fine ?