Amniotic fluid low!

I am 30weeks 4 days had my appointment today the dr said that my amniotic fluid is low a 9 to be exact he said to go home rest and drinks lots of water there is nothing they can do they ck the umbilical cord to see if the baby is unde stress but the baby was fine anyone out there going through the same thing what are your dr'a saying. If my fluid goes as low as 3 then he said things will change and send me to the hospital am nervous but I am not freaking out!