Sleepless in SA

At night, as light fades, cells in the retina of the eye send a signal to a cluster of nerve cells located in the hypothalamus, in the center of the brain. These cells in turn send a message to the pineal gland in the brain to produce the hormone melatonin, which causes a drop in body temperature and sleepiness. At the same time, another cluster of nerve cells in the brain is believed to deactivate three major chemical messengers in the body, that keep us alert: histamine, norephinephrine, and serotonin.

Ok, so if insomnia occurs, there's something wrong.
1) It is not night.
2) You did'nt switch off the light.
3) Retina send a wrong signal, she's myopic.
4) Hypothalamus have move out from Central Brain.
5) Pineal Gland was broke, he cant produce anything.
6) Cluster deactivate caffeine and PEA.
7) You keep thinking what have gone wrong.