"It's like a movie. I'm not making memories," says the young girl, "and I'm just like really scared."
This Illinois Teen relives the same day, every day.
Riley Horner wakes up every morning believing it's June 11th -- the day she was accidentally kicked in the head while crowd-surfing at a concert.
The traumatic head injury reportedly causes the teen's memory to reset every two hours.
Speaking to WQAD on Monday morning, she said she wouldn't even remember being on the news by that evening.
"I have a calendar on my door and I look and it's September and I'm like 'Oh, woah'," Riley said. "I'm very confused and I try to think back... and I can't."
In school, the former athlete has to carry around all of her belongings, because she can't remember where her locker is. To keep up with schoolwork, she also has to leave very detailed notes, take photos of them on her phone, then set an alarm to go back every two hours and try relearn what she has forgotten.
Her mother Sarah said doctors have not been able to determine what exactly is wrong; they initially believed it was a simple concussion, and sent her home on crutches.
"They tell us there's nothing medically wrong. They can't see anything. You can't see a concussion though on an MRI or a CT scan. There's no brain bleed, there's no tumor," said Sarah. "They told us that she might just be like this forever. And I am not okay with that."
Riley's uncle recently passed away, and her mom said she has to keep breaking the devastating news over and over. "My brother passed away last week and she probably has no idea," she said. "And we tell her every day but she doesn't have an idea about it."
Riley added: "I know it's hard for them as much as it's hard for me. And people just don't understand. It's like a movie. I'm not making memories ... and I'm just like really scared."
Sarah is pleading for help from anyone with knowledge of the condition, as research has shown that issues with short term memory can lead to irreversible damage if not addressed within six months.
"We need help," she begged. "We need somebody that knows a little bit more because she deserves better. I mean she wanted to be in the medical field and now she can't even hold a job if she wanted to."