The 43-year-old singer said that she puts a lot of pressure on herself because she is always trying to juggle her parental responsibilities with her sons - Kingston, 6, and Zuma, 4 - with her L.A.M.B. clothing line work and her commitments with No Doubt.
In an interview on This Morning, she said: "Well, you don't plan for it to all happen at one time. Like, 10 years ago, I said, 'Oh I want to start a clothing line so I can do something creative, for when I have my kids and I can be home and I won't really be doing music'.
"And then here we are! We're doing like everything at once and I'm like, 'Oh no!' It's super hard. Every day is a challenge and I don't know, like, it doesn't work most days but some days you get up and it's all good."
Stefani fell pregnant with her second child in 2008, the month after completing 106 live solo concerts, and having had her first son Kingston while on tour.
The popstar - who is married to Bush rocker Gavin Rossdale - admits her pregnancy ruined plans to reunite with No Doubt that year but is pleased the group are finally back together for their new album Push and Shove.
She said: "I had gotten pregnant [with Kingston], went on tour pregnant, and then had the baby and went on tour. It was crazy.
"I nursed the first baby for like 14 months on tour while doing shows, and then the month I got home I got pregnant with Zuma and that was the month No Doubt were gonna get together to start to write the record. I was just a bit dictated."
Watch the video for No Doubt's 'Push And Shove' below: