Some people find they feel depressed in winter, or suffer from "winter blues".
Seasonal affective disorder (SAD) is a type of depression that comes and goes in a seasonal pattern. SAD is sometimes known as "winter depression" because the symptoms are usually more severe during the winter.
The exact cause of SAD isn't fully understood, but it's often linked to reduced exposure to sunlight during the shorter autumn and winter days.
If the short, dark days are getting you down, the NHS has information on SAD.
For some people, the symptoms can be severe and have a significant impact on day-to-day activities. A range of treatments are available and your GP will recommend the most suitable treatment programme for you.
Disclaimer: If you are worried about specific health issues, please seek professional medical advice.