Low amniotic fluid and partial separation of water bag from uterine wall

At my 20 week anatomy scan I found out i had very low amniotic fluid so i was sent to a high risk OB who confirmed and also notice separation of the water sac from the uterine wall. Anyone else have this? Any suggestions? I was just told to drink lots of fluids and rest and they will check me every couple weeks but if they have to that they can deliver at 24 weeks. The baby was perfect and measuring a few days ahead, kidneys and bladder were functioning which was a concern with the low fluid. So they are not sure the reason for low fluid. I was concerned that I could have been leaking fluid but they couldn't find anything.