Feel like giving up

I don't feel like giving up, now that I think of it, I am. I got a knife the other day, I don't cut myself, more like leaving dents in the skin that heal quickly. I don't even have the guts to cut myself. I was told by my boyfriend that it's not cowardly to not to do it, but for me, everything is a question of being brave enough to do what you want to do, and what I wanted to do was this. 
There are so many things I've wanted to do but I've been to scared even though I'm sure these things would make me happy, but I don't do them in case I'm punished for feeling something. I wanted to punish myself for not doing it though, so, cutting, hurting myself, it seemed like the best option and I dreamed about it, hating myself for wanting it. When I finally got the chance to do what I wanted, it wasn't what I expected. I hated myself even more. Why could I do this? Why couldn't I do the only thing that could make me happy right now? Why am I such a coward? Don't I realize what a waste of life this is? I'm a waste of breath.