I'm depressed, poor, and don't feel comfortable being alive. What do I do?

If you were to ask anybody that knows me, but isn't close to me, they would say that I'm the happiest person in the world.  They think I don't get stressed by anything and that I'm always fair.  That's really who I want to be.  I'm so sensitive though to EVERYTHING.  So much is capable of ruining my day.  I used to be able to tell when I was legitimately upset by something, but now I can't tell the difference between my depression and the things that are supposed to upset me.  It's ruining every part of my life.  I've been having stress attacks at work.  I'll cry if I drop anything or have to do anything that involves using problem solving skills.  I feel useless.  I'm living with my boyfriend, who has always been good to me, I think, and takes care of me everyday.  And yet every other day I want to break up with him.  I make his life miserable because somedays I am so thankful and appreciative for what he does, because he does a lot for me, and yet other days I don't see anything but the negative.  I'm moving out because I don't want to hurt him anymore.  I'm paranoid and defensive.  So many times I think about how nice it would be if I happen to die today.  I don't want to kill myself, but I feel like I shouldn't have been born anyway, so it'd be a good thing if I died somehow today.  I'm sick of this taking over my life.  I want to appreciate the good things again.  I can't afford anything though.  I don't have help.  I'm scared that I'm going to have to get rid of my dog because if my motivation keeps on dropping like this, I'll have no right to own a living thing.  I want to be a dog trainer.  I have so many goals in life that I feel I'll never have the motivation to accomplish.  I don't want to be another loss to suicide.  I'm sick of my brain telling me that I can't be happy.  I'm scared.