I had same problem with fluids and found i could drink 500ml or so about 1/2 hour before eating when there was no food inside. i drank this as soon as i got up before breakfast and then drank in small amounts as often as i could. i got some sports bottles 500mls each to measure it out trying to get through 4 of them. I also drank tea. Sounds lime your fluids are letting you down. you know your body will retain if it not getting enough fluid