The 'Lucky Day' hitmaker - who went her separate way from bandmates Sarah Harding, Cheryl Cole, Nadine Coyle and Kimberley Walsh in 2009 - struggled to decide what to do with her life when the group began their break but she didn't want her management team to decide her future career for her.
She said: "Before I started making the album, I felt so frustrated that I wasn't making music and I felt like I couldn't see music in my life for a long time. I didn't know how I was going to have music in my life until the band had another record.
"It really made me sad. I felt like I wanted to be a singer and I used to write little and then all of a sudden the band went on a break and management were trying to find different things for me to do, this TV work, that TV work, and it was just like, 'This is really sad, actually.' Really not sitting well with me at all.
"I was frustrated and angry inside every day. That's what the song 'Fish Out of Water' [from album 'Cinderella's Eyes'] was about, what, am I supposed to just find another career because the band is on a break? That's how I felt."
Nicola, 25, recently claimed the girl band would be getting back together next year for their 10 year anniversary, but would record any future album very differently from the past.
She said: "We'll make this album differently. If we make a record.
"I'm a different person. I've grown up a hell of a lot since we made our last record. So it's going to be different."