If you are going to lose weight or gain weight you must believe that you can do it. If you are discouraged, you will not be able to do it. You must think,I CAN LOSE WEIGHT. I WILL LOSE WEIGHT. I WILL GET HEALTHY STARTING RIGHT NOW!
This may seem a little over the top - but it's not. You need to get yourself into a healthy mindset. You need to give yourself positive reinforcement and pump yourself up.
You may need some help to get into a healthy mindset. It is not a weakness to admit that you need help. In order to be a healthy person, you have to admit that sometimes you just can't do it by yourself. You may need the help of a trained professional (a doctor, a dietician, a personal trainer) or simply a support network of friendly people. If you have tried to do it on your own and have failed, then it is time to get the help that you need - start with your family physician.
Your support network can be composed of people that are available for you to talk to, they should be positive people and they should believe in YOU.
If you don't want to count on your friends and family - you may need to go out and pay for a diet plan - Weight Watchers, Jenny Craig, NutriSystem are a few of the programs that also provide a support network of actual people you can talk to and find encouragement from.