Yes, Stay positive, forgive yourself, you will make mistakes.
Also, this isn't rocket science. you MUST eat 900-1200 calories a day, or you won't lose weight, no whining if you are cheating and not losing weight. I know everyone says it isn't a diet, but really it is. I can't eat like a fat person and lose weight, I have to eat like a skinny person. I see hundreds of posts on here about not losing weight, it's that simple, don't follow the diet, you won't lose weight.
Also if you are not banded yet. Not everyone gets sick and pukes all the time. I've never had a single problem, never PB'd, no food has ever been stuck.
The band is for hunger control. When filled properly, your hunger should cease for 4 to 5 hours. I would say look for that, instead of "restriction" because the band won't stop you from eating.. there is a hole in it, food goes through. If you are eating your 900-1200 calories a day you should be satisfied. Whereas pre-band I would have been starving all the time.
Don't snack or graze. Everything had calories, it can sabotage your diet.
Eat as much Protein as you can, but I don't think you need to be obsessive about it, or drink Protein shakes. i haven't had a shake since my post opp liquid diet. Remember those shakes can have hundreds of calories, they are Meal Replacements..
Also, it's all mental, 90% of this battle is overcoming food addiction. You have to change your habits.