The actress, who joined the BBC One soap in 2005, was told in April that her character Honey Mitchell would be written out. She filmed her final scenes for the programme a few weeks ago.
Barton told The People: "I was gutted when they told me. I know that's the nature of the job and nothing is forever but I didn't want it to end so soon."
Emma also complained that her exit is being seen as a minor event in comparison to the death of the show's long-standing dog Wellard.
She admitted: "I can't believe I've been upstaged by a dog dying."
The soap star does not have any work booked until December, when she will play Snow White in a Christmas panto. She has confirmed that she is "up for anything", but hopes to reprise her career as a musical theatre performer.
Meanwhile, Perry Fenwick, who plays Honey's husband Billy, has voiced his disapproval of the decision to axe Barton.
"They said the character had come to a natural end but what does that mean? It's gutting for Billy and for me," he explained. "I'll really miss Emma. Don't get me wrong, I'm happy where I am but I do wonder what's next for my character."