The 30-year-old singer, who gave birth to daughter Aoife Belle in March, believes that not being able to breast feed due to musical commitments contributed to her baby blues.
"I got quite teary," she told The Mirror. "They call it the fourth day blues. I really missed being pregnant and having her to myself.
"When she's out there, she's out there for everyone to look at. She's not just yours anymore."
Healy added: "The fact that I wasn't going to breastfeed her made me feel a bit of the blues. I would really love to, but because of work and everything I wasn't able to.
"I just knew it wouldn't be practical to be performing on stage with big leaky boobs full of milk."
She is currently engaged to English rugby player Ben Foden.