Amy Duggar King felt a lot of pressure to look “perfect” while on 19 Kids and Counting.

Amy, 38, sat down with PEOPLE ahead of the release of her new tell-all memoir, Holy Disruptor: Shattering the Shiny Facade While Getting Louder with the Truth, out Oct. 14. She opened up about life in the Duggar family and in front of the camera — and the intense pressure she felt to look her best.

While she and her family were filming 19 Kids and Counting, Amy was financing most of what she wore on camera, like clothes, makeup and hair products, she tells PEOPLE.

“I was scrambling to keep up … I definitely felt it,” she says. “I realized millions of people were seeing me, and I was like, ‘Oh my gosh, I have barely any money at all to do this. How am I going to do it?’ And thank God for Goodwill and Dollar Tree, because that’s how I survived, literally.”

“I definitely felt like I should look perfect all the time,” she continues. “I wanted to keep my skin clear, I wanted to look a certain way and have the newest thing, and (be) stylish and all that.”

Amy says the rise of social media likely contributed to the pressure she felt. At the time, Instagram was just starting to become popular, she says, and its impact on self-image hit her “like a ton of bricks,” she says. She also was putting pressure on herself, she recalls.

Looking back, she estimates that she spent “probably thousands” constantly refreshing her wardrobe and cosmetics. She didn’t want to wear the same thing twice, she says — a notion that still stays with her to some degree.

“It’s kind of bad, but once I wear something, and someone sees me in something, then that’s that moment in time — and now I’m going to sell it or get rid of it,” Amy says.

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But since she gets most of her clothes secondhand, the practice is fairly sustainable, she adds. “I still love thrifting, till this day, because of my grandma. She taught me that. She was like, ‘Amy, let’s go thrifting. We can find you stuff.’ And so I keep that memory alive, and that’s why I thrift today.”

Amy’s new book promises to share “her unfiltered testimony of breaking free” — from expectations, labels and the powers that be. She reflects on her years on 19 Kids and Counting and addresses how she’s healed “in the years since the Duggar family collapse,” per the book’s synopsis.

Holy Disruptor: Shattering the Shiny Facade While Getting Louder with the Truth is out on Tuesday, Oct. 14, and available for preorder now, wherever books are sold.