First of all - cast that shame away. It's not going to help you lose weight. Losing weight is the best thing you can do for your body because you love your body, it's the ultimate gift.
Second of all - tell us what you were doing to lose weight before. Calories, exercise plans, food plans - the works. I am sure we can help you determine what went wrong and how you can improve. There's always room for improvement, I've been tweaking my plans for years now and I'm still learning.
Third of all - YOU CAN FREAKIN DO IT! Believe in yourself! You sound so fed up with your situation so use it as a catalyst to begin a life where you can be proud once more and never give up!