Timing of meals?????
I know every doctor has a different post-op diet, but one thing I was told is to never go more than 4 hours without something. (I was able to start on regular food one week post op, supplemented with 2 protein drinks a day) You want your blood sugar to stay stable and I think that is what is causing your weak, yukky feeling. Not sure what you can eat, but remembering to not go too long between nutrition is a good idea.
I have not had any issue with drinking my water at all. From the time I was given water in the hospital right after surgery. I have been drinking water only for about 2 years already with 1 cup of coffee a day. I don't know if that makes it easier. I really have no secret - I wish I did so it would help you!! I drink literally all day long until I go to bed. Sip, put down the water bottle, wait a couple minutes and sip again and repeat over and over.