The Bachelorette's J.P. Rosenbaum on His 'Scary' and Rare Disease: 'I Am Lucky to Be Okay'

"I still can't do all the things I once took for granted," says J.P. Rosenbaum of his battle with Guillain Barre

For J.P. Rosenbaum, Friday, Dec. 6, began as a normal day.

Despite waking up with some tightness in his hands, the Miami-based real estate entrepreneur, who has been married to The Bachelorette‘s Ashley Hebert since 2012, went to work and then had lunch with a friend.

But by the afternoon, “I started noticing stiffness in my calves and ankles,” Rosenbaum, 42, tells PEOPLE exclusively in this week’s issue, opening up for the first time about his terrifying ordeal. “I wasn’t walking right.” By the time he went to pick up a pizza dinner for his two children, Fordham, 5 and Essex, 3, his mysterious condition had worsened.

“I couldn’t hold the pizza box with one hand,” he says. “When I got home, I dropped my keys, and when I went down to pick them up, I couldn’t get back up. I had to brace myself against the car to climb my way back up.”

Hoping he’d be able to sleep off the symptoms, Rosenbaum went to bed, but by the next morning, “I got in the shower and I couldn’t manipulate the soap around my body,” he says. “Ashley had to help me put on socks and underwear and I said, ‘I’m definitely going to the hospital.'”

J.P. Rosenbaum.

An MRI and a lumbar puncture (or spinal tap) revealed telltale signs of Guillain Barre, a neurological condition in which the body’s immune system attacks the nervous system. Prognoses of the rare disease range from weakness in limbs to full paralysis and necessity of a ventilator.

The severity of the condition “didn’t hit me until the next day,” Rosenbaum says. “I was definitely very scared.” Miraculously, however, thanks to an administering of immunoglobulins (or healthy antibodies to combat those that were attacking his system), his symptoms had already begun to plateau, indicating that it was unlikely that his situation would get any worse.

“I am lucky to be okay,” Rosenbaum says. “That has not escaped me.”

After two days in the hospital, Rosenbaum returned home, where he attempted to adjust to his new normal.

J.P. Rosenbaum, Ashley Hebert. Presley Ann/Getty

“It’s the strangest sensation,” says Rosenbaum, who has persistent weakness in his hands, forearms, shoulders, triceps, calves and feet. “Your mind thinks you can do something, but your body just won’t do it. When I walk, my calves feel very tight, and I have to be careful, because if I fall, I can’t brace myself. I can’t pick up a pencil or button a button or tie my shoes. The other day it took me over an hour to shower and 25 minutes to put on my shorts and underwear. Eye-opening is an understatement.”

• For more, pick up this week’s issue of PEOPLE, on stands Friday

Rosenbaum is currently undergoing five days a week of physical or occupational therapy, working to regain the strength that he’s lost. Full recovery can take from few weeks or months, up to a year.

“I still can’t do all the things I once took for granted,” he says. “It’s perspective altering.”

Nonetheless, “I haven’t gotten angry,” he says. “Before, I wouldn’t have said that I was an overly positive person. But this experience has changed me. And I know how fortunate I am. This [condition] put my life into perspective. I hope I can carry that feeling with me forever.”