Baby measuring small having c section tomorrow

Hi All, our baby is measuring small and they believe he wil be about 4 pounds (I'm 36 weeks today). I'm booked in for a c section on Monday as baby's growth is starting to even out on the charts. Has anyone been told their baby was small and then was bigger than expected? Or has anyone had a 4 pound baby? How long did they have to stay in hospital? How easily did they put on weight? Any comments welcome just feeling anxious about it all! I am praying my baby boy will be ok