First things first. STOP! Take a really deep breath, exhale fully and repeat several times. I am REALLY proud of you for recognizing you may have food issues and want to stop those patterns to prevent this surgery from failing you as well.
There is a difference between actual hunger and head hunger. You should not be experiencing actual hunger so early out of surgery. Therefore, it is highly likely to be head hunger and you are in the throes of withdrawal. It SUCKS! :( However, there is great hope! You are learning that obesity is only a symptom of a larger issue for you. And, that issue needs to be addressed in order to deal with food addiction and to lessen your chances at transfer addiction. However, the most important reason to process this (work on your very self) is that you will find happiness that you never imagined. Addiction medicates (numbs out) pain. When you heal yourself of the pain, you will have an entirely different level of happiness and FREEDOM!
So...I would recommend seeing a therapist skilled in eating disorders or if there are other issues you know from childhood, somebody that is skilled in dealing with those areas of trauma. And, the next thing, and equally important is a 12 step support group like Overeater's Anonymous.
Very proud of you,