Daylight saving time is over . The sun will rise later and set earlier, and that can throw off our circadian rhythms.

For a certain percentage of people, the shorter days lead to seasonal affective disorder, a clinical depression.

Seasonal affective disorder alters a person's mood from upbeat, to lacking energy. It's like running at half the speed- mood wise. They spend more time feeling sad, lacking motivation, tired, and might not get much sleep.

Doctor Allan Jacobs says this happens because your body clock is regulated by light, WSFB reports.

"I think it's very curable so to speak so people shouldn't just say 'oh that's winter I'm going to have a terrible time for 5 months,' no. It's useful to take measures to try and feel better," he said.

To cope with the symptoms, doctors suggest light-bulbs that mimic sunlight, exercise, and in some cases, when prescribed by a doctor, antidepressants.