Gwen Stefani is still in shock about her divorce from Gavin Rossdale, telling Elvis Duran on Thursday that the split was the last thing she thought she would be going through this past year.

Her song “Used To Love You” is about her experience with their split after 13 years of marriage, and Stefani said she wrote it during a fragile time in her life.

“Everybody knows pretty much what happened to me," she said, Us Weekly reports.. “I got a divorce, which was completely not in the plan at all.” She added, “For me, it surely wasn't. A shock. A horrible, crazy year and explosion in my life."

Stefani, who's now dating Blake Shelton after reportedly catching Rossdale having an affair with their nanny, also admitted she was "blocked" from writing for the past several years but the tragedy got her creative juices flowing again.

"At that time, I wanted to go in and write," she said of going through that tough time. "I just wanted to be in my bed crying and do what you do when life falls apart . . . Anyways, I went to the studio, and I was convinced that I had to make something out of this. 'I'm not going online and wasting my time.'"