Low amniotic fluid

Hi all, I'm 36 weeks and went into the hospital last night bc I couldn't feel the baby move in a few hours even after trying all the tricks. All was fine with that but they found I have low amniotic fluid. My doctor told the hospital to discharge me if my measurement was above 8 and it was 8.2 so just barely over. So she wants me to come see her first thing Monday morning. I was told to drink more water to help. Any one else have experience with this? What happened? I'm not super worried just wish this didn't happen on the weekend so I didn't have to wait two days until my appointment to check it out again. Thanks for any input!