Trouble with low fluids

Hey Mamas, has anyone suffers from low fluids? I'm 25+5 weeks along and for the past 2 weeks my doc has been monitoring my fluids via U/S. They even took me out of work and put me on bed rest for a week due to this. Now my whole thing is I drink a ton of water, about 6-8 16.9fl OZ bottle waters a day! And still im only at the 10th % and thats only since I've been home from work for the past week. Before I was 9.5 then a few days later I went down to 9.3 and now I'm at 10 since being home from work. Idk what to do to retain more fluids. Any moms have any advice on what I can and should do, I just want my baby to be good😞.