Kourtney Kardashian revealed on a sneak peek episode of "Keeping Up With the Kardashians" that she's pregnant with her third child. The news came as a shock but the family seems to be happy for the 35-year-old mother of two.

Now a new report by British magazine Now, claims that Kourtney Kardashian is reportedly having a really hard time dealing with her sister's third pregnancy.

"Khloe's been praised for being an amazing aunt - a role she embraces as she dotes on her nieces and nephew. But it's only natural that it'll be hard for her to watch her sister carry another baby while her story has been so different," a source told the tabloid. "It's a tough time for her right now."

The source claims that the 29-year-old reality star has been spending more time with her younger sisters Kendall Jenner, 16, and Kylie Jenner, 18, because they're not married and don't have any children. The 29-year-old reality star has always been vocal about wanting a family of her own and her struggles with fertility were even shown on the family reality show.

According to Radar Online, Kris Jenner knows Khloe is having a tough time with Kourtney's baby announcement and told Khloe to be patient and stop worrying about having children.

"With Kourtney so easily having baby number three and seeing Kim's daughter /North all the time, Khloe lets everyone know that she would really like to have her own babies," a source told Radar.

"Kris has told Khloe that she will be a mother one day, but that she needs to wait her turn," the source continued. "Kris pointed out that Kim was 32 when she had North and she wasn't married to Kanye and Khloe is still young. So Khloe doesn't need to freak out, she's young!"

Jenner also reminded Khloe that Kourtney waited until she was older before starting a family with Disick.

"Kourtney didn't have kids until her 30s and Kris told Khloe that too, hoping that she would make her feel better about not having any children now," the source told Radar.

However, the source claims that the fashion designer and reality star is not taking her mother's advice and is still eager to "be a mom."

"She sees how happy Kim and Kourtney are with their children and she wants that too. And the longer she waits the more afraid she is that her time is slipping away," the source said.