The 31-year-old was treated for addiction to sleeping pills and alcohol at the rehab facility, reported Contactmusic.
"I'm 200 percent better in terms of my inner strength and attitude. I'm a lot calmer. I still have my hyper days, but I just take one day at a time. In the band it was a roller coaster. And yes, I have learned from my mistakes.
"I'm just like any normal person, I have a drink. Back then I was going through a break-up. That was then and this is now and, yes, things are different," Harding said.
"I still like the odd night out with my friends and on tour we had an after-party in London, another in Manchester and one in Dublin, which people set up for us," she added.