Night Grammar

I am a curled up comma
When I sleep, so give me pause.
I’m sentenced to insomnia
Which grips me in its clause.

I’m subject to a poor night’s rest;
That’s predicated on
The fact that I have tossed and turned
Each night that’s come and gone.

Don’t question if I’m in control
Or I’ll get out of joint
And answer very forcefully
With exclamation point.

The night’s a restless period
And though I barely sleep,
My colon and its semi-friends
My secrets somehow keep.