The 36-year-old former prison officer announced last week that she is pregnant with her third child, in the run up to the release of her debut album and tour.
She said: "I've had a bit of negativity... Just a few people on Twitter saying 'your career's going to be over' or 'that's your career down the pan'."
She added: "I'm always going to be working no matter what. I'm living proof you can do it, whether you're pregnant or have kids already."
"So many people do it. Myleene Klass does it. Victoria Beckham does it - she's got four and she's still working."
Bailey, who won the last series of the ITV talent show, had to reschedule her tour to make way for the baby.
Some fans took to Twitter claiming: "She'll be forgotten before she has even had success."