36 week check up ! Uterus to big Anyone have this happen? ?

So I am 36 weeks pregnant and due date is November 9. Schedule for c section November 4.

Went to my check up and doctor said my Uterus is to big and that I need another ultrasound to see if the baby is bigger then they are hoping or there is extra fluid. My cervix is thinned but not dilated. When I went for an ultrasound at 31 weeks they said a baby was measuring 2 weeks a head of where I was supposed to be.

Next Tuesday is my ultrasound sound.

Anybody have this happen or ever heard of it ? Of course I look online about extra Fluid could mean something wrong with the baby. I know I should never look at things online.