Today is the most depressing day of the year as millions return to work, a new study shows.
British company Upbeat says the first Monday back at work in January has consistently secured the lowest score for the year on its happiness index.
The Upbeat barometer analysed over 2 million British tweets in January over the past three years, picking out negative comments which indicate mood plummets in the month.
It was revealed that tweets relating to guilt were nearly five times higher than average on this day, as people head back to work and bemoan their inability to keep New Year's resolutions.
It provided a daily score between 0 and 100 to deliver a happiness index. The first Monday back scored 49 on the barometer.