December 11, 2019 | 11:10am | Updated December 11, 2019 | 4:50pm

A 17-year-old Florida girl died from mononucleosis after her symptoms were repeatedly missed by doctors, her family said.

Ariana Rae Delfs, who attended Fernandina Beach High School, first started to complain three weeks ago that she felt ill with a headache, news station WJAX-TV reported.

“She had cold symptoms,” her father, Mark Delfs, told the outlet. “The persistent thing all the way through was a headache. She seemed to always have a headache.”

She underwent several tests, but doctors were unable to determine what was wrong and treated it as a cold, he said.

Her dad said her health took a turn for the worse one night when she started “constantly” throwing up.

“We got very nervous, so the next morning at 7 a.m., we said we’re going to take her to the hospital,” he said.

At the hospital, she stood up at one point and was not able to feel her legs, the outlet reported. Doctors suspected the teen was having a stroke and she was airlifted to another hospital.

“Her words were very slurred at times,” her dad said. “She was just talking gibberish, and the damage was already beginning at that point, which we just didn’t know.”

It wasn’t until her final days that doctors diagnosed her with Epstein-Barr virus, which is better known as mononucleosis, the report said.

“Her brain swelled to the point where it couldn’t function and brain damage did occur,” her dad said. “And we just made the decision that it was time to let her go.”

Her family is speaking out to urge others to be proactive and visit the doctor when they’re feeling ill.

“In our case, it wasn’t enough, but in somebody else’s case, it may save their life,” he said.