Im taking water pills for fluid and im drinking close to 72oz of water a day and im not peeing as much as i should be.

First, your fluid intake is too much for a patient who needs water pill for either kidney, heart or liver disease. Your total fluid intake (fluid in your trays + drinking fluid) should be limited around 42-45 oz a day. Second, if you drink that much but you can not void much because your current water pill is not strong enough due to your disease. At the end result, your body fluid is higher.