"If I didn't have them I don't know if I could be as strong as I am right now," Kayla Gaytan tells PEOPLE

When Kayla Gaytan finished five months of chemotherapy in May 2016, her doctor told her she would likely never be able to conceive.

The next month, she received the good news that her Hodgkin’s Lymphoma — a cancer of the lymphatic system —was in remission. And what followed was more good news: she was pregnant with quadruplets.

“I called my husband to tell him and he couldn’t believe it,” Gaytan, 29, tells PEOPLE. “He thought he had misheard me.”

The Fort Campbell, Kentucky, mom of two and her husband, Sgt. Charles Gaytan, were preparing to welcome the quads to their family when the unthinkable happened.

Credit: Courtesy Kayla Gaytan

In December, Gaytan received the devastating news that her cancer had returned.

“With four babies on the way, I just couldn’t wrap my head around how it could come back,” she says. “I thought I had beat it the first time.”

The quadruplets were delivered via C-section at 30 weeks on Dec. 30 so that Gaytan could begin the treatments doctors hope will save her life.

Credit: Courtesy Kayla Gaytan

“They say I have a 50 percent chance of being here within the next five years,” she says. “But I don’t have a choice but to fight. I have an amazing husband and family that need me.”

Because they were delivered early, the quadruplets will remain in the hospital for the next month. Gaytan will start chemotherapy again in two weeks, and then undergo a full stem cell transplant.

“Now it’s resistant to most chemotherapies because it came back so quickly,” she says. “But all we can do is hope that there’s a higher power with a different plan for us.”

Gaytan says the quadruplets, whom she visits at the hospital daily, and her two older children, Ethan, 11, and Harper, 2, are giving her the strength to carry on.

Credit: Courtesy Kayla Gaytan

“If I didn’t have them I don’t know if I could be as strong as I am right now,” she says.

She’s sharing her story in the hopes that she can share this strength with others.

“You really never know what tomorrow’s going to bring,” she says. “You can have four blessings come into the world and then get devastating news.”

“But you just have to deal with it and stay positive and not give up,” she continues. “Because once you give up it’s going to be harder to fight in the long run.”

A GoFundMe page has been established to help with the family’s medical expenses.