(Editor's note: This article originally appeared on Babble.com. It has been reprinted here with permission. The Walt Disney Co. is the parent company of both ABC News and Babble.)

Every woman who has ever been a teenage girl (ahem, everyone) knows the pain and heartbreak of being left out. You’d think such inconsequential things would leave us behind in middle school but, unfortunately, it’s one of those silly, yet undeniable things that follow us into adulthood. I may handle it slightly more maturely and with fewer tears, but that doesn’t mean it hurts any less.

Every weekend at least one of my friends cracks a joke about “FOMO,” the humorous acronym for that feeling we all get but don’t usually want to admit when something fun is happening and we’re not part of it. You know, the Fear of Missing Out.

Usually, it happens when you do something not because you really feel like it, but because you don’t want to be the only one not doing it. It’s only funny because you know exactly what I’m talking about.

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But what about when it’s not funny anymore? When the fear of missing out isn’t a fear at all, it’s a reality, and it’s not your choice. When missing out becomes being left out.

In middle school, being left out meant not being asked to sit at the right table or not being invited to dinner with all your friends before the school dance. It meant not having someone save you a seat in the bleachers during pep rallies or having your friends all get together after school and not include you. Things that to adults seem miniscule or irrelevant, but to a teenage girl practically mean the entire world.

As you grow older you learn those things weren’t quite as important as you thought they were back then. You may not remember all the exact situations, but you still remember what it felt like. You learn not to do that to other people and to speak up for yourself when you’re not included and, most of all, you learn to “put on your big girl panties” and brush it off.

You’d think with all the practice we get growing up we’d have mastered these necessary skills by adulthood. The skills needed to not let things affect you. To not be hurt by the actions of others. To look on the bright side. But I have to admit, as an adult and, as a mom especially, I don’t quite have it down yet.

When you’re in the early stages of parenthood, just learning the ropes and adjusting to a completely new way of life, friends suddenly take on a much bigger role. They fulfill a need you might not know you had as you navigate the array of emotions that come with learning to be a mom.

They’re the ones who keep you from going crazy and help get you through your day. They’re the ones who get you out of the house and to play dates or girls’ nights. They’re the ones who pick you up when you’re down.

Until they don’t.

Inevitably, you won’t be included in everything. Occasionally, it’ll feel like you’re included in hardly anything. Sometimes it’s a play date or a trip to the park. Other times it’s a girls’ night out or a weekend getaway to someone’s beach house.

Maybe it’s just grabbing a quick bite for lunch or meeting up with the kiddos at the library. That’s when those middle school feelings you thought you’d shoved way down deep come back with a vengeance.

It doesn’t matter that you’re fully grown and raising your own little ones now; it’ll sting just like it did way back then. (The difference now is that you can’t go home crying about it to mom and have her make it all better with a hug and some ice cream. Although ice cream still helps.) Perhaps because the need for friends (read: allies) in this big parenting world is so great, that’s why it hurts so much.

Twenty years ago, I imagine it might have been a little bit easier; you may never have known you were even left out of something. But now, in the world of social media and instant photographic gratification, everything is documented and shared. That means even if they never tell you about it, you know.

You know that everyone in your playgroup went to the zoo or the splash pad, or you know your friends went out for drinks last night and you didn’t. And even though you know you’re not supposed to worry about it because you have more important and better things going on (kids! life! family!), every once in a while it still has the ability to cut you to your core.

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