Finn Wolfhard is opening up about his “crazy whirlwind career” that came with starring in the cult-favorite Stranger Things as a teen, along with his plans post-series.

The It actor made his name in Hollywood in 2016, at the age of 13, with his role as Mike Wheeler in the Duffer brothers’ hit Netflix show. But in an interview with GQ magazine, published online Wednesday, he expressed the impacts of finding fame so young.

During the early years of his adolescence, he said he was fine and “did not talk about anything” because “there was no time, or at least we didn’t feel [there was] at the time.” But then at 15 or 16, the actor said he started having routine panic attacks.

“Everyone was like, ‘Look at him, he’s fine. He’s having the best time,’” he continued. “But in reality, I was probably also developing and things were happening in my brain and anxieties were forming and things that I didn’t realize that I had to bury because of how I had to feel at work.”

More recently, the now 20-year-old actor said he also had a panic attack while filming When You Finish Saving the World, which was released in January. “I was so uptight and nervous about it because I just was like, ‘This is the first movie [that I’m doing] as an adult,’” he recalled.

In turn, he said Jesse Eisenberg, the writer and director of the A24 film, who has also been in the industry since he was a teen, reassured him and told him about experiencing his own panic attack while on the set of Adventureland.

Over the last few years, the actor said he has tried to maintain as much of a normal life as possible by living in a rented house with friends in L.A. and even going back “to real high school” in Vancouver before he graduated.

Following the fame and attention that came with the success of one of the streamer’s top series, he said at times it was “weird.” From an influx of social media followers to clips of him and his character shared online, he said, “I remember seeing them and respecting that people were using this to be creative, but also being so uncomfortable and being like, ‘Whoa, this is weird.’”

Wolfhard will return to join the gang in Hawkins — well, actually Georgia — when filming starts for season five this spring. He told GQ that he was “stoked” after watching season four and thought, “Oh, hell yeah. Let’s finish this.”

He continued, “It’s going to be nuts to finish it. It’s going to be amazing, but it’s going to be nuts.”

As for his career post-Stranger Things, the actor said he’s “not concerned with being relevant at all, ever. I’m just concerned with the people around me and the jobs that I’m doing day-to-day.”

“When things feel really overwhelming and big, it can feel even more big to kid actors who just feel like it all can be gone in an instant,” he added. Wolfhard said the idea of taking a break can be scary, even for some of his colleagues, but he tries to encourage them to do so. “Actually, it’s necessary,’” he said. “It’ll keep you alive. It’ll keep you better at your job, too.”