The holidays are over, New Year’s resolutions have been broken, and you can’t seem to shake your cold. Tired and overwhelmed, or just downright depressed? You're not alone. Blue Monday — typically the third Monday of the new year — is called the most depressing day on the calendar.

Started as part of a publicity campaign by Sky Travel, this notable date was first published in a press release by psychologist Dr. Cliff Arnall, who at the time worked at the Centre for Lifelong Learning, part of Cardiff University in Wales. Arnall devised a literal mathematical formula to arrive at the Blue Monday theory. It factors in weather, debt and time since Christmas, timing of New Year’s resolutions, low motivational levels, and the urgent feeling that you need to take action. It also reflects that Monday is regarded as the worst day of the week with many dreading the prospect of returning to work.

The Guardian calls Arnall's mathematical formula "arguably hokey." As The Guardian reports, "This dubious bit of math was used to give academic weight to a press release put out by Sky Travel to encourage people to cheer themselves up with a holiday."

How to combat the blues on Blue Monday? Well, Arnall said not to turn it into a self-fulfilling prophecy. "I'm pleased about the impact it if it means people are talking about depression and how they feel but I'm also encouraging people to refute the whole notion of there being a most depressing day and to use the day as a springboard for the things that really matter in your life," Arnall told The Telegraph.

If you're feeling the winter blues, there are things you can do to boost your mood. Go for a walk outside even if it's cold. Change your diet and eat these mood-enhancing foods. Don't let the cold weather and dark days be an excuse not to exercise. You can still have an effective workout at home during the winter.

Whether it's folklore or there is truth behind it, don't let Blue Monday drag you down after the holidays.

Editor's note: This article has been updated since it was originally published in January 2016.

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