The Nickelodeon alum also revealed her team told her she was "crazy" for wanting to leave acting.
Jennette McCurdy says she was "deeply unhappy" and "resented" her life at the peak of her "iCarly" fame.
On Wednesday's episode of her "Empty Inside" podcast, the former Nickelodeon star shared more details about what led to her decision to walk away from her acting career, which she described as "hellish."
McCurdy famously starred as Sam Puckett in "iCarly," which ran from 2007 to 2012. She then reprised her role in the "iCarly"-"Victorious" spinoff "Sam & Cat" alongside Ariana Grande.
"I was a famous 19-year-old and making a bunch of money and I felt like I had everything at my fingertips," began McCurdy, 28. "But I was deeply unhappy and I actually really resented my life because I didn't like the projects that I was a part of."
"It's a difficult thing to say because the shows that I was on were so loved by so many people and so many kids and I hear constantly, 'You made my childhood,'" she continued. "And I think that's great that they had that experience. But that just was not my experience and I felt a lot of shame -- that I wasn't able to identify at the time --- because I didn't like waltzing onto an over-lit, cheesy set and shouting a line. It felt so pointless and shallow."
In addition, McCurdy said she struggled with her identity at the time because she was "very different" from the character she was playing.
"To be known globally for this thing that's not really me, it was just like, What the f--k am I doing?" she explained. "How do I even find myself when I'm 19 and I've been famous for all the years that I would normally be stumbling through finding myself, yet I'm known as a thing that I'm not. It just was -- 'hellish,' I think, is not too intense of a word."
After McCurdy's mother died in 2013 following a 17-year battle with cancer, McCurdy wanted to quit acting as it was her mother who got her into it in the first place. However, when McCurdy, who was 21 at the time, told her team she wanted to change careers, they called her "crazy."
"So when my mom died, I was like, I don't want to act anymore. I'm going to leave this career that my agents and my managers and everybody I know is telling me I'd be crazy to leave," she said, before recalling people telling her, "'How can you walk away from this? Are you kidding, do you have any idea how many people want what you have?'"
"But it didn't matter because I didn't want it -- it just wasn't true to me," she added. "And walking away was really difficult, but it was something that I needed to do for my mental health and for my overall peace. And it was difficult. I didn't know what to do with myself when I didn't have things that always dictated my identity around anymore. When I didn't have my mom, when I didn't have acting...that was who I was. So who am I now without the two things that made me who I was?"
After she went through a "very difficult process," McCurdy was ultimately able to find herself.
"I'm living a life that's more true to myself, that I feel more aligned with myself, that I don't feel like I'm living this lie," explained McCurdy, who transitioned into writing and directing. "I'm living a life that's in accordance with who I am and that feels a million times better."
The podcast episode came just a couple of weeks after McCurdy first opened up about her decision to step away from acting, revealing she quit years ago. Due to the fact that she felt "embarrassed" of her role amongst other things, it seems pretty unlikely that McCurdy will be joining her former "iCarly" co-stars for the show's reboot at Paramount+.