I wish I had something helpful to say. I couldn't read your post without replying. I know what it feels like to think that nobody understands how much pain you are in. Then you get so angry because you feel as though you are pouring your guts out but nobody cares anyway. It's like you're screaming at the top of your lungs, "help" but nobody hears.
Would you consider showing someone what you have posted here. Write down how you feel and show it to someone. I know it can be so hard to put it into words sometimes. I can act as if nothing is wrong but really I am dying inside. Tell someone about how you feel, even if you have to write it down and let them read it.
Sorry that you feel so bad. It's hell isn't it.