I'm really nervous that I won't physically be able to have Brynn vaginally because of how bad my SI…

I'm really nervous that I won't physically be able to have Brynn vaginally because of how bad my SI joints are. I can't lay on my back without a lot of pain much less sit up if I am in a laying position. Im in physical therapy but it's still getting worse and my pelvis is just too weak. I'm absolutely terrified of having a c-section..