All the Exes Who Attended Kourtney's 40th Birthday Bash

The reality star breaks down in tears as she turns to Khloe for support.

Turning the big 4-0 really took its toll on Kourtney Kardashian.

In a preview for the seventeenth season of "Keeping Up with the Kardashians" -- yes, Season 16 just ended and we're already looking ahead to the fall -- the eldest sister has a mini meltdown as her big birthday approaches.

"Are you happy?" Khloe Kardashian asks Kourt in the clip, a question for which her sister doesn't exactly have a clear answer.

"I do think that turning 40, it almost makes you analyze like, where you're at in your life," Kourt explains. "It's just giving me anxiety."

As for what's leaving Kourtney feeling anxious, she says that ever since she launched her Poosh lifestyle website, she finds herself always wishing "I had more time."

It's then she breaks, telling Khloe she feels like she wants to cry before doing just that. "It gives me anxiety and I don't know why," Kourtney adds, "I have so much and I should just be so happy."

Though she says that she is happy, she often also finds herself thinking, "What am I doing?"

"I'll just do stupid shit to distract from really thinking about stuff that is maybe more important," Kourtney adds. "I don't know. But then half of me is like, live your life. Have fun."

Though Khloe tells her to do whatever "makes you happy," she doesn't truly believe her sister's "soul is happy." She adds, "I think you feel incomplete somewhere."

"Keeping Up with the Kardashians" returns for a new season in the fall, premiere date TBD.

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