Don't be discouraged; just pick yourself up and move on. Maybe you should take a look at your diet and see if there are any things you are eating that are causing you trouble.
Sometimes diet products can be saboteurs, because they sound and look healthy but are really full of artificial stuff that isn't good for your body.
You know more than anybody what things cause you the most trouble.
When I was on a low-calorie diet, things like rice cakes and granola bars were a problem for me because they were addictive and not filling enough. I would end up eating too much, because I thought they were healthy. Maybe you just need to tweak your diet a little. Don't be bummed out..you can do it!