If you woke up feeling grumpier than usual this morning you're probably not alone, as experts reckon today is one of the gloomiest days of the year.
Researchers say the third Monday in January is when people are more unhappy than at any other time in the year.
Apparently it's all to do with the grey and depressing weather, breaking our New Year's resolutions and not having much cash to splash in the shops!
It's become known as Blue Monday and this year falls on 19 January.
Cannot play media. Sorry, this media is not available in your territory.
Kids' views on blue Monday
But it needn't be all doom and gloom - Dr Mike Isaac gave us some of his top tips for cheering yourself up...
- Keep busy - exercising or playing games can boost your mood
- Surround yourself with bright things
- If you're watching TV, choose something that will make you laugh
- And remember... you're not alone. Feeling down at this time of year is very common