Low amniotic fluid

Went in for my 20 week ultrasound today. Doc said all looked good and healthy. Baby is little tho ranking at 38th percentile for growth. One other thing she mentioned was I have low amniotic fluid. She told me I need to rest/drink plenty of fluids and stay in ac when possible. I do have to go in for a follow up ultrasound next week to see if anything changes over the week. Has anyone experienced this as well? She says not too worry but of course I do and then I made the mistake to google "Low amniotic fluid" and that has now made me even more nervous! Agh!