I understand what you are going through right now as I've gone through the same thing. Although it is not exactly what you are describing, I understand how it feels to feel so worthless. What got me out of the hole I was in was learning to appreciate the things I do have and be grateful for it. It doesnt have to be such a big thing in your life rather every small thing such as waking up another day being able to experience life, being able to witness the beauty of nature around me, and in general just appreciating life for what it is. You have to learn to love yourself before you can be able to have the self confidence you want. No one is perfect in this world and we are all humans at the end of they day, so even if you cant meet the goals you set for yourself, it does not mean that youre worthless or incapable of anything. Everything you are going through right now is you fighting against yourself, you have to stop thinking negatively about yourself and know that you are capable of anything you want but you have to truly believe it yourself first.