'American Idol' Alum Jax Reveals She Was Diagnosed With Thyroid Cancer

American Idol alum Jax showed her fighting spirit when she clawed her way to the No. 3 spot on season 14 of the singing competition, but the fight of her life came after the show.

In an interview with My Central Jersey, the 20-year-old singer revealed that she was diagnosed with thyroid cancer in April shortly after performing at a concert.

WATCH: 'American Idol' Contestant Jax Wore #TheDress!

"It was very unexpected," Jax said. "When you're 20 years old, you have this Superman entitlement mentality. Like you're indestructible. Thank God I have people in my life that were there to help me deal with this when my reality finally clicked for me. I'm a tough guy, but I don't think I have ever experienced anything scarier."

According to Jax, she felt a lump in her throat while grocery shopping and got herself checked out at an urgent care facility. After undergoing tests, it was revealed that she had 18 tumors on her thyroid, 12 of which were cancerous.

Jax said that she felt "depressed" and was in a "really dark place" in the days leading up to her diagnosis.

The work, pressure, & travel in music is not always so forgiving on the mind and heart. It absolutely takes its toll on your body. Sometimes I think the universe is yelling at me to slow down and I just blatantly ignore it. I have always been obsessed with my job and craft, so stopping and breathing isn't easy for me. However, my health has to come first. I understand that now. Recently my family and I were given a serious wake up call... As I was recording and doing press out on the West Coast, I noticed that I was waking up in a very dark place everyday. Stress has always been a weight in my life, but over the course of a few weeks something felt different. I was losing my voice often, and struggling to keep my eyes open and my moods/energy consistent. My happiness was the last concern on my priority list and my folks new something was definitely up. So, long story short, I came back home to NY for a bit (we had just sold out my first homecoming show since tour at Webster Hall in Manhattan) to rehearse. While grocery shopping with my parents, I felt a small lump on my throat. We really didn't think much of it, as I mentioned I tend to ignore bumps in the road (pun intended) for the sake of speed and production. I was homeschooled so my lame immune system is always giving out on me. Either way, my mom and dad thought it would be a good idea to check it out just in case, so I went in for some ultrasounds and tests (via Urgent Care believe it or not). A few appointmets later, I was definitively diagnosed with Hashimoto disease. The doctors found 18 tumors on my Thyroid...Which would explain what I had been going through emotionally. I'm pretty convinced after all this that my Thyroid is more important than my actual brain. After that diagnosis, my Thyroid specialist wanted to double check and biopsy the tumors to make sure they were not cancerous. It is unlikely for Thyroid cancer to occur in younger people. I went into the hospital for a biopsy on the tumors, performed my show at Webster Hall, and got a call from the hospital a few days later. It turned out that 12 out of the 18 tumors tested positive for cancer...Continue reading at Crowdrise.com/JAXPACK❤️

A photo posted by JAX (@jax) on Aug 8, 2016 at 8:11am PDT

"People don't realize how important the thyroid is. It's more important that the actual brain," Jax said. "It was messing me up emotionally, putting me in a strange place."

After surgery, all of the tumors were successfully removed and Jax is currently undergoing iodine treatments.

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"I'm radioactive right now," she said.

In the midst of her recovery, Jax is not letting the setback slow her down. She's planning to participate in the 2016 TCS NYC Marathon on Nov. 6 to help raise funds for Tuesday's Children, an organization dedicated to helping youth and families affected by terrorism.

"Sometimes I think the universe is yelling at me to slow down and I just blatantly ignore it," she wrote in an Instagram post on Monday. "However, my health has to come first. I understand that now."