You have to give yourself time. I could never have participated in a social gathering like you did with friends so early after surgery. Make the first month after surgery time to spend on you alone. What really helped me was the group therapy sessions I participated in before the surgery. After meeting for the initial psychological test, I was recommended to join a therapy group for seven sessions. It was help by the hospital psychologist. Those sessions really helped me deal with the "mind" aspect of my cravings and my bad behviors with food. We set small goals and changes in behavior every week and it really helped once I had the surgery. You may want to seek out some therapy. Hope you find it gets easier!