The best motivation is to do it for yourself.
If you really want to lose the weight, set a goal and take one accomplishment at a time. From the sounds of it, the diet is what's hurting you. Take the advice in this thread (4-5 better balanced meals during the day; even a bowl of cereal could suffice for a meal - NOT Count Chocolat
), and it will shed off.
Best of luck with your goals.