Your worth is not about the number - be it on your scale or your report card or your bank account, or anything that can be compared by its nominal value to whatever "standard" you think you should meet. Strive for it, but don't make it out to be a binary situation - you either have it and you can live, or you don't and you're a worthless waste of space. Everything is progress. Focus on positive progress.
Your worth is not about how many people "want" you or some arbitrary quality you think they should want you for. Why do you think there are so many miserable women who are attractive, skinny and successful? how many of them are trapped in joyless, unfulfilling relationships with shitty people because they put their worth into how much someone else needs them around. Unless you're a radioactive mutant from space, you can find someone who will be attracted to you physically. And if you have half a brain and a pulse, you can find someone who will want to depend on you emotionally. What's in it for you? validation? for what? your right to exist? Focus on what you want, who you will be happy with, not someone who will put up with you despite shit. If you continue to tie your self worth into how much others can get out of you, that's how you'll live your life - being taken advantage of and constantly justifying your existence. Fuck that.
Jobs, hobbies, losing weight - these are your projects. Projects that can benefit you mentally, financially and physically. So treat them as such. Make a plan and follow through. If you stumble or face a temporary setback, big deal, nothing ever works on a first try. Correct this error an move on. As I said, it's not about some arbitrary quantifier, there's always going to be someone younger, skinnier, smarter, richer, more successful, don't waste your life chasing things for the sake of comparing them to others. It's a moving target and no matter how much money you make, how much weight you lose, how many hot guys you date, it will never give you inner peace.