"I was working seven days a week, sleeping in the factory. I was in the paint shop, general assembly, body shop," Musk told HBO.
Asked if he worried about himself "imploding", Musk said, "Yeah, absolutely. No one should put this many hours into work. This is not good. People should not work this hard. They should not do this. This is very painful. It hurts my brain and my heart."
Prior to hitting its production target Tesla was facing around US$1 billion ($1.4b) in debt repayments — around US$230 million due in November — without enough cash coming in to keep the company running.
"I've said before that we must prove that Tesla can be sustainably profitable," he told reporters during last month's earnings call. "This quarter was an important step towards that."
Musk has informed patient customers who paid deposits for their Model 3s as early as March 2016 that the first Australian deliveries will take place "around mid-2019".
After taxes and import duties, the cheapest Model 3 will be around A$80,000 ($85,132) drive-away, putting it on par with a Mercedes-Benz C300 or Audi A4 2.0 TFSI quattro.
The high-profile chief executive of the electric carmaker has endured a tumultuous year marked by personal and professional scandals.
He stepped down as chairman last month as part of a US$40m settlement with the Securities and Exchange Commission, which alleged Musk misled investors with a series of tweets in August suggesting he had funding in place to take the company private.
Musk is also being sued for defamation by British diving expert Vernon Unsworth — who helped in the Thai cave rescue earlier this year — for calling him "paedo guy" in an extraordinary Twitter attack.