What is The Fury?

The Fury is here
present in My chest
clutching and heaving
rising and falling
with every breath
like a coiled snake
prepared to strike

feeding off My air
stealing My food
a parasitic disease
growing ever stronger
It needs a deep breath
My body gives it willingly
The Fury has my lungs

coursing through My veins
It extends through My arms
down into My fingertips
where The Fury meets a fist
My weak attempt at resistance