When you're grumpy or simply not acting like your usual self, people are quick to say that you've "woken up on the wrong side of the bed."

We've all had days where we've had to drag ourselves out from under the covers.

The only thing on our mind is going back to sleep and hopefully waking up on the "right side."

Unfortunately, on these days, most of us have to crawl out of our beds and go on with our daily lives.

Maybe you've never thought of the expression as a fair statement, but according to new research, there may be some validity to it.

A study by Penn State University revealed that the way you feel in the morning has a huge impact on your day.

So if you wake up with a negative mindset and stress yourself right from the get-go, you're almost guaranteed to have an awful day.  

"Humans can think about and anticipate things before they happen, which can help us prepare for and even prevent certain events," lead author Jinshil Hyun said in a statement.

"But this study suggests that this ability can also be harmful to your daily memory function, independent of whether the stressful events actually happen or not."

This study doesn't prove that waking up on your left or right side will put you in a bad mood, but the idea that you think it does will ultimately affect the rest of your day.

To prove this point, the researchers recruited 240 people to be part of their two-week experiment.

Each participant was asked to rate their stress levels in the morning, and then at night.

The researchers found that people who anticipated to have higher stress levels in the morning had an overall stressful day.

They also had poorer cognitive performance than those who woke up in an optimistic mood.

Simply thinking about how your day will unfold has a huge impact!

Martin Sliwinski, the co-author of the study, believes there are ways to overcome these thoughts.

"If you wake up and feel like the day is going to be stressful, maybe your phone can remind you to do some deep breathing relaxation before you start your day," he said.

"Or if your cognition is at a place where you might make a mistake, maybe you can get a message that says now might not be the best time to go for a drive."

So next time you feel like you've woken up on the wrong side of the bed, take a moment and destress, it will make for a much more productive day.

Have you always believed in this expression?

Here are a few easy ways to relieve your anxiety in the mornings.

And here are 8 famous people whose positive morning routine has changed their life for the better.

[H/T: Business Insider / IFLSCIENCE]