For years we've followed Teen Mom 2's Leah Messer in her struggle to find a diagnosis for her daughter Aliannah. Ali and her fraternal twin sister Aleeah were born December 16, 2009, and it wasn't long before Leah noticed that they weren't developing at the same rate. Leah and her ex-husband Corey Simms finally got some answers in the Teen Mom 2 Season 4 finale, and we'll likely learn more about Ali's condition during the show's upcoming fifth season.

In the meantime, we can rest assured that Leah is doing well and staying strong. Wetpaint Entertainment recently caught up with the Teen Mom 2 star at MTV studios in New York City, where she spoke candidly about how she's been coping.

"I try to deal with it the best way I can. I try to stay strong for Ali," Leah told us exclusively. "Honestly I don't know what I would do without her. I know I probably wouldn't be going through this, but going through this with any other child, I just couldn't image. She has the brightest personality."

For Leah, the hardest part is seeing Ali endure so many hardships at such a young age. "It crushes me," Leah admits, "because she doesn't understand and she's still so full of life. Especially seeing her in her wheelchair for the first time, she just felt so free and so happy."

In the action-packed trailer for Season 5, we see Ali using her wheelchair while Leah says sadly, "My future with her doesn't look so damn bright." But the mother of three swears she'll never break down in front of Ali.

"I don't let her see me weak. I never will let her see me weak," she says. "I am her strength and she's my strength."

And Leah's not the only lady in the Messer-Calvert household showering Ali with unconditional love and support.

"Aleeah is very protective," Leah reveals. "If her sister gets bumped and falls, she'll be screaming at that person, 'Like don't you ever touch my sister!' She knows there's something, but she doesn't understand what."

These girls sure are lucky to have each other!

Are you looking forward to seeing more of little Ali when Teen Mom 2 Season 5 premieres on Tuesday, January 21? Tell us your thoughts below.