Amniotic fluid

Have any of you ladies been told you have low levels of AF around the baby? I went in today for an ultrasound and told me that mine was at a 9 and it was a little low. Doctor didn't seem crazy worried just suggested I drink tons of water and get lots of rest but idk this is my first pregnancy and I've been hung up on it. I don't want anything to be wrong. Has anyone gone through this?