Being a visionary billionaire and chief executive of three companies at once isn’t all fun and games, Elon Musk tweeted Sunday, describing “unrelenting stress” and suggesting he may be bipolar.

Musk tweeted his replies to a number of questions on Twitter, starting with his response to a tweet that said he had “an amazing life.”

“The reality is great highs, terrible lows and unrelenting stress,” Musk tweeted. “Don’t think people want to hear about the last two.”

When someone else asked if he was bipolar, Musk replied “Yeah,” but then followed up with: “Maybe not medically tho. Dunno. Bad feelings correlate to bad events, so maybe real problem is getting carried away in what I sign up for.”

Musk continued: “If you buy a ticket to hell, it isn’t fair to blame hell ... I’m sure there are better answers than what I do, which is just take the pain and make sure you really care about what you’re doing.”

Medically speaking, bipolar disorder is more than just mood swings, often involving low energy levels, inactivity and inability to think clearly, and should be diagnosed by a psychiatrist.

While the chief executive of Tesla Inc., Space X and Neuralink may be flying high at the moment, Musk has had his share of business failures, nearly died from malaria in 2000 and has been divorced three times.

Read: The many failures of Elon Musk, captured in one giant infographic

On Friday, Musk handed out the first of Tesla’s highly anticipated new Model 3 sedans, telling employees, “Welcome to production hell” as the company gears up to mass produce the vehicles.