It starts with a small trigger:
A word, an image, an object
That brings your thoughts back to
Them

It knocks the wind out of you
You don't want to remember
Yet at the same time you do

Then the memories invade your brain
Take over your very being
Render you immobile

Everything goes tight
Eyes squeeze shut
Fingers, a vice around the nearest table
Trying not to let this be your undoing

Finally the pain subsides
Passes over you like an ocean wave
Leaving you sapped of energy and full of relief

But the relief quickly turns to dread
Because you can't help but wonder
When this ****** cycle will start again