fluids (and purees for the most part, too) go right through you, so you won't feel full. You'll start to feel the restriction once you start eating solid food.
also, you've had nerves cut, and it takes them awhile to start to regenerate - which again, that should start up again about the time you move to solid food, too.
also, keep in mind that your "full" signals (once you start feeling them) might be different than they were before surgery. Mine are different - I get this uncomfortable pressure in my chest, and I know if I keep going, I'm going to be sorry. I've read about other people getting a runny nose or sneezing when they're full. It might take some time to figure out what your new "full" signal is, too..