Heidi Newfield, who skyrocketed to country music fame as the lead singer of the hit country trio, Trick Pony, is finally speaking out about the reason for her departure from the group, and her newfound success as a solo artist. With her first single, 'Johnny and June' peaking at the No. 11 spot on Billboard, and over 100,000 albums sold after only seven weeks, it seems it was, for her, a smart career move.

"I waited, and I fulfilled all of my obligations with them. I didn't quit midway or anything like that. It was tough, " she admitted to CMT. "There were a lot of hard feelings on their part and a lot of bitterness. And they made it pretty hard on me there those last couple of months ... But I felt like I could hold my head up high and left with character and dignity."

Rather than pointing to one specific reason, Newfield admitted it was the culmination of many factors that led to her decision. "We really worked very hard together," she said. "I had no intention of ever going solo once I joined. I suppose the thoughts of continuing on singing on my own just came about in a very natural kind of way [after] we all began to go our separate ways. Musically, I felt like we were really just painting ourselves in a corner. I felt like we were growing sort of stagnant and that we weren't looking for and writing songs that were pushing the envelope. We weren't trying to step outside that lighthearted, honky-tonk barroom kind of stuff."

For Newfield, singing was meant to be fun, and when she stopped enjoying it, she realized she was at a huge turning point.. "...I wanted to keep singing, and I didn't feel like the fact that I was unhappy in the group warranted me ending my career," she says. "So I chose to leave."

The title track of her debut solo album, 'What Am I Waiting For,' was a perfect way for Newfield to express what she was feeling. Penned with bandmates Keith Burns and Ira Dean, and hit writer Jeffrey Steele, Newfield sees the relevance in having Burns and Dean help write what ended up being the launching pad for her solo career. "It's ironic. They were unaware that I was really writing about my feelings about the band at that time."

Newfield is certainly staying busy while promoting her new album. She recently joined forces on the road with several of country's biggest acts, including Dierks Bentley, Brooks and Dunn, Miranda Lambert, Blake Shelton, James Otto, and Montgomery Gentry, and has no plans to slow down anytime soon.

"I've been going nonstop. I just flew in from Atlanta [via] L. A. and Arizona," she says. "I've been all over the map. ... I've not had many days off -- which I am absolutely not complaining about at all. It's really good to be working hard again. I'm enjoying this whole process more now than I think I ever have."