Hillary Clinton is reportedly facing “mounting health issues” that may prevent her from continuing her campaign for the 2016 presidential election.

According to an excerpt from the new book Unlikeable — The Problem with Hillary _ — exclusively obtained by _Radar Online — the 67-year-old politician may be secretly suffering from Multiple sclerosis.

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Hillary has been “frequently plagued” by “blinding headaches” and insomnia for years, author *Edward Klein * wrote in the new tell-all, which hits bookshelves on Sept. 28.

hillary clinton

Hillary at a campaign event on Sept. 19, 2015.

“[The insomnia has especially] worried her, because it sapped her energy just when she needed it most for the campaign,” Klein noted.

In 2012, the former first lady was hospitalized for treatment of a blood clot located in her sinus. Her doctors discovered the clot during a follow-up visit for a concussion Hillary had sustained nearly three weeks earlier during a scary fall.

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Since then, Hillary has been “constantly worried she [is] developing another blood clot,” Klein wrote in his book. “For the first time I’ve known her, she’s showing self-doubt about her strength and vitality,” a friend of Hillary’s told the author.