"It was constant and first, I didn't think much of it, but it lasted two weeks before I thought it was an issue," said Knox.
Her mom knew something was wrong.
"She looked horrible, you know when you look at someone's face and know there's something wrong? She looked like she was in pain," said Susan Knox.
At the center, doctors diagnosed and treated Anna's migraines, something not done in previous visits to other doctors and specialists. It's a good thing to treat migraines as soon as they begin in the teen years.
"We know that the natural course of migrants is worsening over time, increasing frequency, severity, so to stop that form happening we intervene early, especially in the adolescent population," said Dr. Joshua Cohen.
Where doing poorly in school may be the result of fatigue and trouble concentrating, two symptoms seen often in teenage sufferers.
Migraines can be caused by surges in hormones so girls get them at ages 12-13. Boys start with migraines at age 5-8, and the role of male's hormones isn't clear.
What is clear is that over the counter drugs may help, but prescription drugs are often needed to prevent the headaches and to treat them if they break through.
Dr. Cohen adds that eating regular meals, exercising and getting enough sleep can reduce attacks.
"These things may be difficult for them to accomplish but to the degree they're able to, they're going to feel a lot better," he said.
Anna now has only a couple headaches a month, controlled quickly with medication. Dr. Cohen advises to see the doctor if your teen is having headaches that come back regularly, to make sure nothing other than migraines is causing the problem, and to get the right diagnosis and treatment.