With just five pairs left competing in Dancing With the Stars' All-Star Season -- and a double-elimination going down during Tuesday night's show -- Shawn Johnson knows she can't just cha-cha her way to victory.

Still, as the Olympian confessed to Us Weekly backstage after Monday night's performances, she had no idea how tough things would actually be at this stage of the game. (This week, each pair had to prep not one, but two separate routines: a mashup of an unexpected style and theme, plus a dance to a hit Michael Jackson song in honor of the 25th anniversary of Bad.)

"This has been the week from hell for the entire cast," Johnson, 20, told Us. "It's been one of those weeks where we were thrown stuff we weren't used to, and it's a semi-final, so you want to take the chance to show everyone what you're capable of. But when you're given [our assignment] a Knight Rider Bhangra [mashup], it kind of limits that. Mentally, it shut everyone down."

Despite her pre-show exhaustion, Johnson and her partner Derek Hough managed to score a perfect 30/30 from the judges following their Bhangra routine.

"I don't know what happened!" the gymnast exclaimed. "I really don't know. It's been a long week and I am so proud of what we pulled off. We brought a choreographer in and we couldn't have done it without him, he was amazing. He met us at the end tonight and said, 'I'm so proud of you guys!' so that felt good."

This article originally appeared on Usmagazine.com: Dancing With the Stars' Shawn Johnson: "This Has Been the Week From Hell"