David Nail experienced one of the highlights of his career when he earned his second No. 1 single for 'Whatever She's Got' earlier this week, which also earned platinum status and became the fastest-rising single of his career.

But the singer admits the career accolades seem even more sweeter because of a private pain he has been battling, that he has remained silent about -- until now.

"To be honest and blunt as I could possibly be ... I've been depressed my entire life and just dealt with so many insecurities," he admits (quote via CMT). "And it kind of came I guess to a head a couple of years ago. 'Let It Rain' was No. 1, and I had all these good things going on, and I just wasn't happy."

The Missouri native says he knew there was something wrong, but wasn't ready to face the issue until his career was already in full swing.

"I was having a conversation with Chris Young at the ACMs a couple of years ago," he recalls. "I remember walking away and being so blessed to have been at this party and so many nice things that were said. And I should be on top of the world, but I just couldn't physically get there or mentally get there."

Fortunately, that moment became pivotal in getting the treatment he desperately needed.

"I've been going to counseling for a couple of years now and take a lot of really expensive medicines and just made a lot of changes in my personal life," Nail shares. "I've learned to not take life so serious and learned to enjoy it and had a lot of help in doing that."

The singer-songwriter says thankfully, he is doing better than ever these days.

"I have a lot more good days than bad days now, and there's a lot of people responsible for that," he says, adding that his wife, Catherine, has been his biggest supporter.

"She's just been there," he notes. "And there have been so many moments where I wouldn't have blamed her for leaving. I think she always believed there was a little bit of light at the end of the tunnel. ... She's just a trooper. She's the first to admit it's a contract we signed through thick and thin, through sickness and health -- 'I'm in this committed ... 'til death do us part.'"

Nail's latest album, 'I'm a Fire,' will be released on March 4. Pre-order the album here.