Nightmares.

I am not sleeping, nor am I dreaming. But why it is nowadays I have such fearsome thoughts running through my head. Thoughts of sharp saw penetrating my skull, thoughts of being tied with layers of metal around my hips until my pelvis bones crush, thoughts of having brain cancer, thoughts of something blocking my vein until the blood pressure causes it to burst. What signs does it bring? Why do I have such thoughts, even when I am fully concious? This is really worrying me...