KANSAS CITY, Kan. — Gray Gaulding’s throat started to swell. Then came the chest pains. And his body began to go numb.

The Xfinity Series driver for SS Green Light Racing was on a Stewart-Haas Racing plane Friday morning to Kansas City when he began to have health issues, leading to the plane making an emergency landing in St. Louis and medics rushing on the plane to help Gaulding.

He said everything was fine when he boarded the flight Friday morning. It left Concord-Padgett Regional Airport in North Carolina at 7:45 a.m. ET.

All was fine for the first 45 minutes of the flight. About 10 minutes after he had eaten a piece of homemade beef jerky, Gaulding said “I could feel my throat slowly start to swell up.”

Chest pains followed. His throat continued to swell. His body then began to go numb.

“I thought I was having a mild heart attack or something,” Gaulding told NBC Sports shortly after being cleared to drive in today’s Xfinity Series race at Kansas Speedway (3 p.m. ET on NBC).

“I went to the flight attendant and I said, ‘Hey, I need oxygen right now. She comes back and gives me oxygen and puts the mask on me and I feel like I’m going to pass out, the eyes are starting to roll back in my head. My arms, all my limbs were shaking so bad that I couldn’t control them.”

As Gaulding took oxygen, “a lot of the Stewart-Haas guys and the flight attendant were so amazing. It felt like they almost saved my life just by talking to me and keeping me awake. They’re like ‘Please stare me in the eye. Look me in the eye.’ ‘’

Gaulding’s condition worsened.

“I told the (flight attendant), you need to tell the pilots they need to land the plane now,” he said. “I can’t make it. I can’t make it. Literally, in two minutes I can feel the plane start to go down.”

The plane made an emergency landing at St. Louis Lambert International Airport at 9:19 a.m. ET. Emergency crews rushed on the plane.

“As soon as the plane landed, they opened the door, the firefighters came in and helped me get off the plane,” Gaulding told NBC Sports. “My limbs were shaking so bad I couldn’t even walk under my own power. They got me off and the medics just started going to work on me.”

He was treated in an ambulance and soon began to feel better and the swelling in his throat went away. He had told the plane not to wait for him and it left an hour later.

Gaulding remained with Jake Vrabel, a member of SS Green Light Racing who was also on the plane. Vrabel drove Gaulding across the state to Kansas Speedway. They arrived during the first Xfinity Series practice.

“He stayed with me the whole time,” Gaulding said of Vrabel. “I had no family, no parents (with me). He drove me while I slept the whole time, helped me eat and everything. He was my saving grace all day (Friday).”

Gaulding went to the infield care center and was further treated and given medicine. He was not cleared to drive the car Friday. His first lap in the car was in Saturday’s qualifying after he was cleared.

That beef jerky could have caused his health issues stunned Gaulding.

“I asked the doctor about it, I’ve eaten beef jerky my whole life, I love beef jerky, I’m not blaming everything on the beef jerky … but the thing is, the doc looked at me and said you could get stung by a bee 40 times and the 41st time your body changes all the time and you could be allergic (to a bee sting) and you could almost die,” Gaulding said. “That could almost be my case. I’ll never pick up beef jerky (again). I’m done with beef jerky.”