The mother-of-two said that during the weekend she questioned whether her sacrifices would be worth it - but has now decided to give it her all.
She is one of five acts who has won through to the semi-finals on Saturday.
Rebecca, from Liverpool, said: "I just found myself on Saturday night thinking 'is it going to be worth it?' - and I got emotional about it.
"And it just made me more determined to go out on Saturday and give it my all," she added.
She said the pressure of being away from her children had got to her.
"I was just missing my kids, if I'm being totally honest. I've worked really hard and it's been a big sacrifice for me being here away from the kids.
"I've missed their birthdays, I've missed the first day of school."
Speaking at a secret X Factor live show for communications firm TalkTalk, Rebecca defended herself against criticisms of her static live performances.
"You've got to think of artists like Adele, for instance. She's an amazing artist. She stands there, she sings. Amy Winehouse is pretty much the same. Maybe that's just the type of artist I am," Rebecca said.
X Factor Star Rebecca Ferguson
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