I know exactly where you are coming from. I had my op date sprung on me with one week's notice so no chance for a grand last supper, which is what I would have loved! Fortunately, I had been to an eat-all-you-can Chinese for my brothe'rs birthday celebration the Saturday before.
I had a hasty fish 'n' chips (with no Vimto to wash it down!) which I shared with my eldest. Food always tatses better off your Mom's plate, eh?
I did go into a bit of a maudlin head rant over 'missing food' but then thought 'what the fook was I going through all this for?'
And believe me, when I woke up in pain and realising I couldn't eat for 28 days anyway, I *knew* the game was up.
I saw a bariatric psychologist before my op and it was the best thing that has happened, aside from the op itself. The stomach is easy to control - the surgeon does that. But once he has made you neat, stepped away from the table, it's you who has to put the effort in.
The head is always a tough one to control, because it is knotted up with emotion and learned behaviours which we need to face and unlearn.
Don't go hard on yourself, take it a day at a time and keep on reminding yourself why you are doing what you are doing.
Good luck and keep talking x