I’m on my second pregnancy 😍😍

My son was born at 36 weeks at 7lb 4oz, no huge problems besides learning how to control his own sugar due to me being a type 1 diabetic. His lungs & all organs were perfect! Now I’ll be 15 weeks tomorrow & my dr wants me to start progesterone shots. I’m sure everything will be okay. I just don’t want to have a 10+lb baby & have to have a C-section. I want to be able to give birth naturally like I did with my son. What has everyone else experienced with the shots?