I think it's interesting that this question will get different answers depending on where you are at in life when you respond to it.
I posted a big list of things I'm proud of because I'm in a good place right now and I feel like kicking butt in life. A month ago? It wouldn't've been so positive.
Sounds like you're living under your own personal rain cloud at the moment Obi, which is OK. You'll get out from under it in due time, just like I will probably get back under mine at some point (and then out again). Cycles of life. Your value as a valid human being is intrinsically part of yourself because you are a living, breathing person and with that fact always comes potential for good and for love. Nobody can fulfill that potential to the maximum all the time, but on the flip side, it's basically impossible for someone to be "just a waste". Your pain and your experience and your perception of life cannot help but contain some grain of truth and light within it, no matter how buried it gets.