measuring big and in pain

I went in at 36 weeks this past Friday and they said I'm measuring at 39 weeks. I'm worried I might need to have the baby early.. I go in Wednesday for ultrasound and will know then what the dr wants to do but I'm in a lot of pain. Pelvis feels broken and I can hardly walk. I read somewhere that some women have been induced when they had this same problem. Anybody have any reassurance for me? I'm going crazy worrying!