This Monday, if you don't feel like heading into work or school, don't bother. The experts have decided the day is already doomed.

More specifically, what the "experts" have decided is that Monday, Jan. 17 is "Blue Monday" -- the most depressing day of the year.

It's a day when the afterglow of the holidays has finally dimmed, when the weather is likely rotten, when the bills from the holidays have crushed down upon us, and when we've realized we've failed -- yet again -- in our New Year's resolutions.

The date is, of course, a bit of a fabrication. It was invented in 2005 by Cliff Arnall, a former psychology lecturer at the University of Cardiff, Wales, who was paid by a travel company to devise a formula for finding "the most depressing day of the year" in order to encourage Britons to book a holiday.

Here's his perhaps deliberately complicated equation:

[W+ (D-d)} x T to the power of Q, divided by (M x NA)

Put another way: (W) weather plus (D) debt minus your monthly salary, multiplied by (T) the time since Christmas, (Q) time since failed quit attempt, divided by (M) low motivational levels and (NA) the need to take action.

The figures might seem stacked against us, but take heart: while there's not much we can do about the weather, there's plenty we can do about our motivational levels and our failed New Year's resolutions.

Ian Newby-Clark, an associate professor of applied social psychology at the University of Guelph, says the first step is not to beat ourselves up about our broken New Year's resolutions.

Instead, we should commend ourselves for recognizing that there's something about ourselves that needs changing and for making what he calls a "self-change decision." We should then reflect on why we failed and then figure out how we're going to get back on track.

Newby-Clark says New Year's resolutions are too often vague and made hastily on New Year's Eve. It's no surprise then, that those plans often fail.

"Resolutions that aren't made with full resolve are going to be the ones that do not succeed," he told CTV.ca in a phone interview.

So there's no point in vowing to eat better, he says, if we haven't thought through how we're going to do that and how those around us are going to support us in that goal.

"You need to make meal plans, and then plan when you're going to go to the store, and when you're going to prepare these foods, and where you're going to eat them," he said.

The other way we fail in our goals is by making them too difficult to achieve, he said.

"People often make resolutions that involve changing habits. But habits are, by definition, highly-ingrained behaviours that are virtually automatic. Those kinds of behaviours are difficult to change. So what can you do about that? One, is to acknowledge to yourself that you're going to change a habit that's going to be hard to change. So set a reasonable goal," he said.

"If your resolution is to yell at your kids less, don't expect to go from always yelling to suddenly never yelling."

He advises making a few small "milestone" goals that are easier to achieve, rather than one large lofty goal.

"There's nothing like achieving a small goal to make you feel like you can achieve more. Most self-change is gradual and incremental. So set your sights lower than your eventual goal to make it achievable, so you can hit the goal."

So instead of spending "Blue Monday" grumbling about the bills, the depressing grey skies, and your winter blues, vow to spend the time planning how you'll get back on track with you New Year's resolutions.

And then start looking forward to June 17.

That's the day that Cliff Arnall -- this time, paid by an ice cream company -- has decided is "the happiest day of the year."