I get that doomed feeling too, but not the self-harm part, so i don't know that anything I might say could help but I'll try...

Sometimes I forget to breath deeply. It's like the anxiety and dread of life, wraps me in a ball and makes me afraid of occupying space in the universe. It is worse in the morning... I just try to remember to breath and remember that it will not always feel the way it does when going through a rough stretch.