John Podesta, the chairman of Hillary Clinton's 2016 presidential campaign, told CNN's Alisyn Camerota on Wednesday that he loses sleep "every night" with the "burden" of having lost the Electoral College to Donald Trump.

Camerota asked Podesta whether Clinton was surprised at how often Trump invokes her name this far into his presidency.

"It's unprecedented," Podesta said. " You never saw that behavior from any other president who's talking about the person they beat. I think it really just bugs the hell out of him that she got three million more votes than he did and he keeps coming back to that."

"Obviously we bear the burden of having lost the Electoral College, so I lose sleep about that every night," Podesta added.

Camerota followed up by asking Podesta what Clinton thinks about being under Trump's skin for winning the popular vote.

"Well look, I think she'll have something to say about that when her book comes out mid-September, and I think she's reflected on the mistakes that she made, what she might have done different, but I think she'll also talk about where the country is and how to move forward," Podesta said. "That's what she's always done in her life when she's gotten knocked down. She's tried to make a positive contribution coming out of that, and I think that that's what this book will attempt to do."

Hillary Clinton's memoir, What Happened, will be a reflection on her 2016 election loss to Trump and will be released on Sept. 12.