It's happened to all of us: Just when you're sure that you wear a certain pant size, you go shopping somewhere new and discover you can't even squeeze yourself into that size. This store-to-store variation in pant sizes is a frustrating phenomenon we've all experienced, which is why one woman's poignant Facebook post struck a chord with women and girls everywhere last week.

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When one of 27-year-old Deena Shoemaker's friends posted to Facebook about a neighbor who had lost her home in a fire and was in need of donations, Shoemaker took to her closet to see if she had anything she could donate. Unfortunately, her good intentions led to an extremely upsetting discovery.

Despite the fact that she's been the same size for years, Shoemaker realized she had pants that ranged in size from 5 to 12. And yet they all fit her the exact. same. way.

Frustrated by the way these fluctuating sizes affect women and girls' self-esteem, Shoemaker took to Facebook, where she posted a collage of six photos of herself in different pairs of pants, each labeled with the size. "No I'm not selling my pants," she wrote at the start of her post. "I've just got a bone to pick."

In the post, Shoemaker explains that she's worked as a "leader and counselor" to pre-teen and teen girls for the past six years, and during that time she's seen young girls obsess over their bodies in worrisome ways. Some she's heard blame their weight for failed relationships; others she's watched struggle with eating disorders. Shoemaker can talk to these girls about Photoshop and the unrealistic expectations that ads and magazines can set for them, she wrote — but what can she do to help them see past the ever-changing sizes of their own clothing?

She wrote:

When you resize a girl's pants from a 9 to a 16 and label it "plus size," how am I supposed to fight that? Photo manipulation is one thing, but how do you expect me to convince her that the number printed inside her clothes is a lie, too? How do you expect me to convince her that she doesn't need to skip dinner for the next month because her pant size didn't *actually* go up by seven digits?

Shoemaker's important message makes a powerful point about the effect that the fashion industry can have on young women — so powerful, in fact, that it's been shared more than 87,000 times on Facebook.

Ultimately, Shoemaker says girls and women of all sizes and ages need to remember that they are so much more than a number on a tag.

"My dear beautiful girls, my size 2 girls or my size 18 girls, your size doesn't determine your beauty; your life does," she wrote.

[h/t TODAY