"During that time period, I was down all the way. You don't go down lower than that," Stefani said. "It was rock bottom."
The 46-year-old singer credits her new album and the new love she's found with her fellow Voice coach for getting her through that rough patch.
"In all of this craziness that happened, I found a friend that was going through literally the exact same thing as me, and that is a miracle," Stefani said. "It just saved me so much. I feel so grateful for that."
On the music side of things, Stefani found solace in the studio by turning her heartache into songs like "Used to Love You" and "Misery." Her willingness to be so vulnerable through her lyrics is paying off, as This Is What the Truth Feels Like held the No. 1 spot on iTunes on Friday, the album's first day of release.
While Stefani is celebrating the fruits of her labor, her boyfriend is also thrilled with the album's success.
"Hey @gwenstefani," Shelton tweeted on Thursday. "My favorite song on your album is 'Rare' ... Just thought I'd let you know."