Nightmare in a damaged brain

My mind drifted in dirt and pain I was so weak and weary,
The sun and also my soul enveloped black and dreary.
Deep into the darkness I stood wondering, fearing,
My heart smoldered deep within.
But it had still continued beating
Nightmare in a damaged brain - all night long
White apparition glided nearby with an ancient grin,
The air grew denser, death perfumed from the ghostly censer.
Nightmare in a damaged brain - all night long
Its eyes have the menace of a Demon,
Its shadow hugs the stony ground.
Do angels borne draw their curtains?
A deathlike shroud never torn.
Nightmare in a damaged brain - all night long
Or am I dreaming instead?