It sounds like you lack motivation. You said yourself that you know what you need to do, but you are just not doing it. So, how can you get motivated? Make a list of all the rewards that you can think of for losing weight. For example, would you like to look 10 years younger? Would you like to be able to go out and buy a new wardrobe when you finally have that slim, sexy body? Would you like to be in great shape and have more energy? What motivates you? Focus on that.