I agree with Joe that people can let you down rather than life itself. Nobody would want to live their life lonely so we have to let ourself rely on some people, sure you may be able to control emotions well and only really trust a few, but I dont think the blame rests at your own feet entirely for allowing yourself to fall back on those you thought cared.
Saying that you shouldnt then feel sorry for yourself for too long. Just stand up tall, look 'em in the Face and say:
I'm that star up in the sky,
I'm that mountain peak up high.
I made it,
I'm the worlds greatest.
And I'm that little bit of hope,
When my backs against the ropes.
I can feel it,
I'm the worlds greatest!
