When I was a little kid, in the 70’s, My mother, a nurse, called it Sundowner Syndrome, way before this term became popular to describe the effects of low-light and evening on patients with Alzheimers/dementia. She described being newly-wed, decades earlier and feeling isolated on a rural property; the feelings of sadness, isolation & emptiness, exacerbated by the setting sun and creeping dark. This explanation has always stuck with me. I feel it too; the gloom of the evening, the perceived, seemingly endless length of the night. I really think that some of us simply react negatively to the dark...nothing to be worried or ashamed of.