Nearly two weeks after checking herself into a 30-day rehab treatment program to "cope with anxiety and stress," LeAnn Rimes returned to her main gig over the weekend, performing an intimate 70-minute set for country music fans in Eau Claire, Wisconsin. Despite her sunny disposition throughout the concert, the singer could not ignore the turmoil that has seemingly plagued her personal life in recent years.

"I'm pissed off at a lot of things, and I just say can't it" Rimes told the crowd, according to People, after admitting she could not ignore the elephant in the room. "So, it comes out in the music."

Of her 14-song set, the singer previewed a few of her therapeutic new tracks, which are slated to appear on her upcoming studio album, 'Spitfire.' Dubbed as "the most honest song I've ever written," Rimes performed 'Borrowed' from the anticipated new project, which was co-written by Dan Wilson, the Grammy Award-winning producer responsible for British pop singer Adele's international success.

"I don't want to give you back. You're the best I've ever had," crooned the country superstar, most likely referring to her scandalous affair and well-publicized marriage to actor Eddie Cibrian.

"On this new record, I guess I bared everything down to the core," Rimes said confidently, speaking about her new studio album. The first single, 'What Have I Done,' will feature Alison Krauss and Dan Tyminski (of Union Station) on background vocals, and is expected to be released to radio and iTunes in December.

Even with a pending lawsuit against two California women for invasion of privacy and a full plate trying to juggle a personal and professional life, Rimes remains optimistic, and seems adamant about coming out of her rehab program a better individual.

"I'm totally cool and so happy; I think I'm about to cry," Rimes told the crowd of her current mental state. "Thanks for being awesome fans – patient and understanding."

The singer's next scheduled tour stop is in Oxford, Maine this Saturday (Sept. 15). While her stay in the treatment facility is ongoing, the singer will check out to perform concerts. Rimes will embark on a 23-date tour this fall to promote 'Spitfire,' which is expected to be released in early 2013. Click here for a full list of the singer's upcoming appearances.