If you haven’t gotten a chance to check your Google Cal today, consider this your superstitious reminder that it’s Friday the 13th. So if you were planning on walking beneath any ladders or adopting a black cat, today is just not the day. Even though this beyond-rare event (which occurs between one and three times per year) has been somewhat ridiculed in pop culture, it actually does pose a legitimate health concern with a nearly unpronounceable name to match: paraskevidekatriaphobia, AKA the fear of Friday the 13th.

Many of those who suffer from the phobia will stay indoors today and may experience symptoms like nervous giggling, suicidal thoughts, increased heart rate, and hyperventilation, according to The Sun. And the condition is more common than you may think. In fact, Donald Dossey, PhD, a folklore historian who founded the Stress Management Center and Phobia Institute in Asheville, North Carolina, estimated in 2004 that up to 21 million people may suffer from the phobia.

Challenge your fears by stepping slightly out of your comfort zone, behavior scientist Dr. Stuart Vyse suggest. It can be, for example, meeting a friend at a café if the fear centers upon leaving home.

A number of factors have contributed to Friday the 13th’s role as a renowned doomsday. (For me, it was a scarring viewing of the Friday the 13th film franchise.) Not only is the numeral associated with a number of devastating events like the Black Friday bushfires in Australia, a freak blizzard in Buffalo, and one of New York City’s most notorious murders, but it’s also widely associated with Judas, the 13th apostle believed to have betrayed Jesus on a Friday. So, a religious view suggests that this fear—irrational or not—has persisted since the advent of the Common Era.

If you, like so many others, experience the date-related heebie-jeebies today, Stuart Vyse, PhD, behavioral scientist author of Believing in Magic: The Psychology of Superstition, tells National Geographic that he recommends challenging your fears by stepping slightly out of your comfort zone. It can be, for example, meeting a friend at a café if the fear centers upon leaving home.

And remember, there’s only a matter of hours left before the 14th rolls around and your normally scheduled weekend sentiments return.

If you’re still not clear on the difference between stress and anxiety, here’s how to distinguish the two. Plus, these are the three things to do next time you have a panic attack.