I've started over more times than I can count. Sometimes that's all I can do!
It sounds like you have very high expectations of yourself, and that's leading to beating yourself up emotionally when you think you are not achieving those expectations. It's OK to have high expectations and goals, but we are all only human after all. There is nothing at all "wrong" with you. You're not defective, or disgusting!
It might really, really help to set a very specific goal. It doesn't have to be a dramatic goal. How can you even measure if you are giving "100%"? I wouldn't know how to measure that. I can, however, count how many glasses of water I drink every day. It provides a yardstick for whether or not I am heading in the right direction.
You can do it!
My Sparkpage is set to private, but I'm open to SparkMail!
"People often say that motivation doesn't last. Well, neither does bathing--that's why we recommend it daily." - Zig Ziglar