A financial expert says too many people have a terrible money habit - and you can fix it in a month

Have you ever logged onto your bank account after a long weekend, only to be hit with that sinking feeling of, Oh my gosh, where did all my money go? You're not alone.

"The worst money habit I see is unconscious behavior," Jean Chatzky, the financial editor of NBC's "Today" show who is also a senior editor at The Balance, told Business Insider in a Facebook Live interview.

"Money has become very invisible, for lack of a better word. It's become largely cashless, it's become swipeable, and it allows us to transact, and spend, and use our money very, very quickly without thinking about it," said Chatzky, the author of several books, including most recently "Age Proof."

While we all know how much we get paid, she continued, "a lot of people have no clue" where that money ends up. "You have to spend less than you make on a consistent basis," she said. "A lot of people have trouble there."

Chatzky says it's imperative to track your money."Pay attention to it for [at least] a month and make sure that you understand," Chatzky said. Understanding where your money is going each month is the first step toward sticking to a budget.  

According to the National Foundation for Credit Counseling's 2017 financial literacy survey, only 40% of Americans have a budget. Forming a budget, especially in your early 20s, is crucial. In fact, one of the dumbest things you could do is ignore your cash flow and spending patterns.

Tracking your money - whether through a personalized spreadsheet or an app like Mint - is the best way to ensure you're keeping up with your expenses, and not overspending in the wrong places. Believe it or not, once you establish the habit, the effort is minimal.

Watch the full Facebook Live interview: