Daylight saving time has ended and "falling back" throws off your internal clock.
A new study in the Journal of Epidemiology showed the number of people with depression increases right after the end of daylight saving time.
JP Morgan Chase research showed that daylight saving time also affects the economy. Buying increases 0.9 percent when daylight saving time begins in the spring and it drops 3.5 percent in the fall.
Daylight saving time started in Germany in 1916 as a way to save energy during World War I. The U.S. started participating in 1918 for the same reason.