Elon Musk is admitting that the stress of his multibillion-dollar companies is taking a toll on his well-being.

“This past year has been the most difficult and painful year of my career,” Musk — the co-founder and CEO of SpaceX, Tesla and Neuralink — told the New York Times on Thursday. “It was excruciating.”

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Musk — who reportedly alternated between laughing and crying during his interview — detailed a life filled with 120-hour work weeks, which has often prevented him from seeing family and almost kept him from making it to his brother’s wedding in Catalonia.

This intense schedule has been the case for the better part of the last two decades, which has spanned Musk’s three marriages, the births of his twins and triplets and the loss of his infant son in 2002 due to SIDS.

“There were times when I didn’t leave the factory for three or four days — days when I didn’t go outside,” he said. “This has really come at the expense of seeing my kids. And seeing friends.”

When Musk turned 47 in June, there wasn’t much of a celebration, he “struggled” to tell the newspaper. He spent the entire 24 hours of the day at work.

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“All night — no friends, nothing,” Musk said.

Because he has trouble resting, the Tesla CEO — who dated actress Amber Heard on and off for years — also admitted he sometimes uses Ambien, a powerful sleep medication.

“It is often a choice of no sleep or Ambien,” he said. The Times reported that members of Tesla’s board have expressed concern about his use of the medication, which can sometimes prove addictive.

The Times interview comes during a tumultuous time for Musk, which has seen him become the focus of controversy, largely due to his social media usage.

When 12 members of a youth soccer team were trapped in a cave in Thailand in July, Musk and engineers from SpaceX helped to craft a submarine to assist in the rescue. Musk was on hand in the country to deliver the machine, but rescue officials opted not to use it. Musk was later criticized by the lead rescuer, Vernon Unsworth, who called the submarine a “PR stunt.” Unsworth also said Musk could “stick his submarine where it hurts.”

Musk sent out a series of now-deleted tweets referring to Unsworth as a “pedo guy.” Musk apologized for his remarks, but Tesla shares took a hit the following day, and Unsworth said he is considering legal action.

Musk found Twitter controversy once again in early August, when he published a tweet announcing he was taking Tesla private for $420 a share, and already had “funding secured.” The message sent Tesla’s stock soaring, but it became the focus of an SEC investigation and reportedly infuriated Tesla shareholders. It also became a meme.

The tweet — which got more than 22,000 replies — led many to believe Elon was using marijuana when he sent it because it referenced “420.” Musk said that was not the case.

“I was not on weed, to be clear,” he told the Times. “Weed is not helpful for productivity.”

While Tesla’s products are largely praised for their technological advancements and has enjoyed success, Musk said he has paid a price for it.

“I thought the worst of it was over — I thought it was,” he said. “The worst is over from a Tesla operational standpoint… But from a personal pain standpoint, the worst is yet to come.”

Image zoom Elon Musk with girlfriend, Grimes Neilson Barnard/Getty

Last week, Musk — who is dating the singer Grimes — was the target of a series of tweets from Azealia Banks, who alleged she spent a weekend at Musk’s home with his girlfriend Grimes. In the tweets, Banks claimed Musk posted his “funding secured” tweet while using acid, and that she was only invited to participate in a threesome that didn’t take place.

A spokesperson for Musk told PEOPLE the claims are “absolute nonsense.”

The Times reported that Tesla’s brass may be looking to hire a No. 2 executive to help relieve Musk of some of his day-to-day duties. When asked if he would consider leaving his role with the company, Musk responded in the negative, but said if there was someone who could do it better than him, he would reconsider.