Ten days after she got the shot at a Reston Safeway, she did get sick.

"I got flu-like symptoms -- nausea, vomiting, body aches, fever -- then was lethargic for a week and started blacking out," said Jennings, an AOL employee and Washington Redskins ambassador hoping to one day be a cheerleader for the team, the Loudoun Times-Mirror reported.

Doctors couldn't figure out why her ability to speak and walk were so adversely affected. She saw neurologists, physical therapists and psychologists.

"I was hoping for Lyme, praying for lupus, even Graves' disease," she said. "Unfortunately they were all ruled out."

Finally, doctors at Johns Hopkins figured it out, diagnosing dystonia, a rare neurological condition with no cure brought on by infections, brain trauma or, as is believed in her case, reaction to medication. It causes body jerks and abnormal or repetitive movements.

"A simple conversation with two people -- you and I could converse on the couch, and if the phone were to ring it would send her into a violent convulsion," said her husband, Brendan Jennings.

Strangely enough -- as she can't walk forward five feet without stumbling -- with some effort, she can perform one of her life's passions: running. And she walks backward with ease -- oddly empowering, now. After her ordeal began, "My insurance wasn't going to pay for another hospital visit. Matter of fact, they called us as we were driving to Johns Hopkins not to offer a specialist but instead to offer a hospital bed and a wheelchair for our house. I told them I wanted to know what was happening to me and that I didn't want to be in a wheelchair."

Her reaction is one in a million, doctors said.

"I would've much rather won the lottery and bought that ticket instead of gotten the flu shot if I knew that risk existed," she said.