First thing you need to do is get the negative talk out of your head. Stop talking to yourself so negatively. You've made a HUGE decision to make your life better, start being nice to yourself. I had the same problem pre-surgery. I ate pretty much everything I thought I would miss post-surgery. Now that I'm almost 6 mos post-surgery, I don't even THINK of any of those things any longer. When I sit down to eat, I often don't get past the protein on my plate. I LOVE vegetables and bread....and don't get me started on desserts, but I'm SO full with the protein I don't even get to move to another option on my plate.
Take it slow, take it easy on yourself, and make it as positive of an experience as you can. Remember, garbage in, garbage out....what you think, you become, so be nice to yourself and encourage yourself! You'll do great!