I can't stand my own mind. (3)
From the jump, we learn that our speaker is having an internal conflict. It's not the kind of conflict about whether or not you should have that second helping of garlic mashed potatoes (you should—everyone knows that garlic mashed potatoes are the best). It's the kind of conflict in which you start to doubt whether your own sense of reality is, well, real. Of course, when you live in a country that constantly does things that profoundly bother you, it's a challenge to stay mentally fit.
I won't write my poem till I'm in my right mind. (7)
This is a tricky line. So, does the fact that the speaker keeps writing after this line show us that he is, in fact, in his right mind? Would someone who is not in his right mind just write something like this and then keep writing anyway? Which possibility gets your vote?
I'm sick of your insane demands. (14)
Sanity, it turns out, is a two-way street. It's not just the speaker who is struggling with his sanity. America, his country, is also insane. Perhaps, then, we get some insight into why our speaker is having his own mental challenges. In a world that has gone mad, can it be truly possible to remain above it all, and sane?