A picture can tell a thousand stories, or in this case nightmares!
I never uses to be a lover of 'dark' poetry, but now I have been taken over by the dark side!LOL
Your poem is a great interpretation of this picture. It is both literal and metaphorical. It has depth and simplicity. In short it is a wonderfully woven piece.
If we allow our fears dictate our actions we will remain its' slave.