I'm glad that you are doing well. If you always have something with you to drink you should be ok on water. Unjury makes an unflavored protein powder that is super easy to mix in anything you are eating.
Now you have to work on your brain, instead of going to food, you are going to have to find a different outlet. That can be anything, sewing, scrap booking, walking, anything! The surgery was a tool for us, now it is up to us to reroute our way of thinking. Now instead of eating when I feel sad, I grab the dogs and family and we go for a walk. So stones I just play a silly game on my iPad to pass the time if I'm thinking about a piece of chocolate cake.
Hope this helps! It will get better, I promise!!