Over my head....

When life seems so unbearable, I was always able to turn for comfort from my closest friends. But now I've realized that you can't rely on anyone... not even the ones you've come to trust. I've noticed a pattern in my life... it seems as though every person who enters my life walks away eventually. My brother assures me that it is part of life and that some people are meant to be in your life while others only make an appearance. If he is right, then why is it that no one who is "meant to be in my life" has stayed? Every person, every friend, I've met began to hate me for no reason whatsoever. What's wrong with me? Is it my fault? I'm losing my mind and my tears continue to fall endlessly.
I feel empty, unwanted, neglected, and useless. If I was meant to stay in this world, then why am I trash to the people I care about? Why did they recklessly abandon me for another person to just pick up and throw away again? If I am meant to be here, then why is it no one has ever tried to show me that I am? I don't know... I just don't know... I won't even bother checking my grammar, spelling, punctuation, etc. I am just too upset to even care at the moment....
I guess it's my fault...