I'm starting to get worried

Something strange has been happening to me. Every day, without fail, I experience an episode of what I'm afraid may be temporary insanity. It usually happens in the evening, a few hours after dark. I become weak and lethargic, my mind becomes sluggish and confused, and I have to lie down. The slightest bit of light irritates my eyes, so I turn off all the lights and close my eyes to shut out annoying bits of light that come in through the windows from the street and neighboring houses. Sounds also become irritating. For a while, random thoughts flit through my brain, but then it happens. Or, rather, without being aware of exactly when it happens, I slip helplessly into an altered state of consciousness in which I lose contact with the outside world. In place of reality, my mind constructs a bizarre farrago of adventures that I experience purely subjectively, involving encounters with imaginary characters and severe contraventions of the laws of physics. I eventually return to my senses, to discover that hours have elapsed, and that I am still lying in roughly the same spot where I was when the frightening lapse in self-control began.