I'm reading what you say, and its not turned to shit.
Like what someone said - the pain IS real, and nobody can argue that one away. But whilst the pain is real - the cause might not be the BIG issue you imagine it to be. A series of problems, no doubt, seem like the Giant Problem.
So lets go through them.
You say its no use getting close to anyone, but you sound to me like your feeling depression. You do know depression tends to lower your self worth (big time) and so maybe you just don't bother getting too close to anyone because your not really in the mood. You want to connect - but depression prevents this.
As for not being able to handle the pain any more - again, its depression. Whatever reason to feel pain is amplified. Have you even tried any medication? You gotta admit, if your thinking you'd sooner be dead then its got to be worth trying to see if some drug might be able to help.
As for nobody caring if you died, this is not true I'm sure. We'd care here, sincerely we would. I don't know you, that's true, but if I passed a lake and heard a splash and the sound of someone drowning (you'd cry out even if your intent was to die) I'd not shout out "is that somebody I know?" - and nor would anyone else.
You think nobody cares - but I'd risk my life to save a stranger - no matter if my life was even looking good.
What you feel right now, all that pain, sorrow and the regrets, that's your own mind working overtime to make a case for the prosecution. You condemn yourself on evidence so flimsy that you'd make a good Witch-finder General. you know - accuse people of being witches. If they drown they are innocent but anyone who floats is surely with the devil!
Try to let us know what you have tried to alleviate the depression.
And like Total Eclipse says - you could meet your soul mate next week. There's no cure for the blues like love. Your plan should be to get well little by little, occupy your time with something which in turn keeps your mind busy. Medication might make it easier for you to initiate the launch sequence for feeling less frantic in your thoughts.
Good luck and let us know what's happening with regards to any treatment.