Dear Anger

Dear Anger,

What am I angry at? So much, it's literally become a physical manifestation in my chest. 
I can feel it, every time I think about just how angry I am.
I can feel it, every time I think about just how stressed I am.
People say it's for the best to let things go, but that can't possibly be true.
If so, how do you know when it's time to stop someone from walking all over you?
But there must be a middle ground. I want to be angry. I want to be a healthy amount of angry.
This isn't a healthy amount of angry.
Sometimes, I accept that I can't change the things that I'm angry about.
Most times, the fact that I have to accept this makes me angrier.
I feel this building in my chest. I feel it. It squeezes my lungs and my blood vessels, it tells my body that it's not fair.
It's not fair.
I can't change these things, and it's not fair.
These things are killing me, and it's not fair.
My anger will kill me, and there's nothing that I can do about it.