A Timeline of Nikki Bella and John Cena's Rollercoaster Relationship

"Every little part of this wedding, it's like, it's going back," Nikki explains.

Weddings usually bring couples together, but the same can't be said for Nikki Bella and John Cena.

In a new preview for this Sunday's "Total Bellas," Nikki explains that the closer their wedding date approaches, the more she feels that she's growing apart from John.

"I feel like I'm continuing to grow more apart from John, and I should be growing closer to him," she says in the clip.

While at high tea with her pals during her Parisian bachelorette getaway, her sister-in-law Lauren Garcia asks if John has any demands for her wedding. Nikki replies that all he asks from her is to "show up."

As we know, wedding planning on her own hasn't been an easy feat for Nikki. The WWE star has had to deal with issues, such as demoting her bridesmaids.

"Every little part of this wedding, it's like, it's going back," Nikki says to her friends.

As always, her twin Brie Bella -- and maid of honor -- attempts to make Nikki feel better and everything has been such a "rollercoaster."

"But you're finally like telling people what you want," one of Nikki's best friends says. "And that's the best part."

"You're finally being honest," Brie adds.

But Nikki doesn't want to voice her concerns to her friends just yet and says she wants to keep the thoughts to herself "for as long as [she] can."

"It's hard when my girls start saying how they love how open and honest I've been in my relationship and how much more I've been using my voice," Nikki says in a confessional. "But I don't want to ruin anyone's weekend and they're all here for me, so even though I'm feeling all these emotions, I just think I want to keep this to myself for a bit longer. As long as I can, at least."

"Total Bellas" airs Sunday nights at 9 p.m. EST on E!

View Photos Getty John Cena, Nikki Bella and Apatow Clan Attend the 'Blockers' Premiere