Teddi Mellencamp opened up about her brain cancer battle and shared how she’s coping with her health crisis during an interview last week, months after doctors discovered four tumors on her brain.

As she shared her chances of survival, looked back on the day her estranged husband, Edwin Arroyave, 47, rushed her to the hospital, and applauded his and Kyle Richards‘ support, the 43-year-old Real Housewives of Beverly Hills alum admitted she’s “really scared” as she explained how she’s using humor to cope and revealed the “hardest part” of her battle.

“One of my favorite things to ask is, ‘How long I got?’ Or, ‘What are my chances?’ And they oftentimes say, ’50/50,’” Teddi revealed during an April 11 interview with Nightline. “I wouldn’t buy a car that’s only gonna drive 50 percent of the time. I don’t want this.”

According to Teddi, doctors explained the 50/50 chances, saying that the daunting figure was the result of immunotherapy being fairly new.

“[My doctor’s] like, ‘No, it’s only because that’s how long immunotherapy has been around, so that’s how long the study has worked’ … Immunotherapy has only been around 10 years,” she shared. “[But] I really like to have control, and this is completely out of my control, and for the first time, I’m like, really scared,”

As she continues to fight for her life, Teddi said she’s learned not to “take anything for granted.”

“Normally, I’m used to running seven miles; today, I’m barely walking one. But you know what? I’m here, and that makes me feel good,” she revealed. “I can’t run, but I can go on a walk.”

In a video of herself on a treadmill, which Teddi shared with Nightline, she was seen getting emotional as she told her Instagram audience, “I’m just trying to remember how grateful I am that I can move my body again.”

Looking back on the day she was rushed to the hospital by Edwin, Teddi said she “couldn’t see.”

“I could barely get down the stairs,” she recalled. “That’s when they said I had four plump-sized tumors in my brain. And then within the next day, I was in surgery.”

“My first real memory was looking up, and my entire family was there … My dad, my sister, my brothers, all of my best friends. And I remember being like, ‘Hold on. Why are y’all here? This must be bad,’” Teddi continued.

Throughout her stay in the hospital, Teddi had tons of support from her friends and family, including Kyle, 56, who often stayed with her overnight.

“Kyle was in the hospital every single day,” Teddi confirmed, noting that she’d also had plenty of help from Edwin, the father of her three kids, Slate, 12, Cruz, 10, and Dove, 5.

“We want to do what’s best for our kids, and I am no longer in a situation where I am able to do everything 100 percent as I was before. Nighttimes are really hard for me, so people come and [Edwin] organizes all that. So, he’s doing the best he can,” she revealed.

Although Teddi’s situation is grim, she’s doing her best to stay positive and find humor where she can.

“I have to. If I didn’t find humor, I would cry,” she admitted. “Even with my kids, like, the other day, we kept forgetting something, and we would all just go, ‘The tumors!’ It’s kind of the only way because if not, I would probably just be crying all the time.”

Teddi’s dad, John Mellencamp, 73, has also lent some much-needed comic relief.

“By the time we get done with this, I’ll have seven missed calls from him. ‘Just checking in!’ But he’s always taught me to be a fighter,” Teddi said of her father. “He’s hilarious. I called him. I’m like, ‘Dad, I’m bald today.’ And he’s like, ‘Well, it could be worse.’ I’m like, ‘How?’ ’You could be dead.’”

As for the worst part of her diagnosis, Teddi said it’s been tough having to slow down and go through physical changes.

“I would say the hardest thing for me is I’ve always been a super active person, and, like, I cannot do the things I was used to doing,” she explained. “I had a cry yesterday when this part went bald. But we sprayed it. It’s really gonna grow out, post-cancer.”

While Teddi confirmed she “sometimes” feels pretty, she also goes through rough moments.

“Sometimes I feel really strong and beautiful and like I could do anything, and sometimes I feel like this might be the lowest and the hardest things I’ve ever done,” she confessed.

Luckily, she’s found a great motivator.

“I would say the biggest thing for me is setting a goal,” Teddi stated. “We have our horse nationals, and the second my daughter and I got in, I made a goal that I’m gonna start getting back to training so that I could do it too.”

“I want to have — now I’m gonna get emotional — I wanted to have the opportunity to do it with her just in case this is my last chance,” she added.