Heather Wheeler, 26, formerly of Ann's Grove primary school in Sheffield, said she received no support from her colleagues.
Mrs Wheeler told the committee that she was appointed as a newly-qualified teacher in October 2001, but was not told that the inner-city school had "serious weaknesses" until she started work there in January 2002.
The school's difficulties added to the pressure that was put on her to improve quickly, she said.
She said her mentor, the school's deputy head Ann Kerslake, was continually critical of her performance and that she soon went off sick due to stress.
Mrs Wheeler said: "If you have got someone looking through your classroom door every two minutes and undermining you in front of your pupils, it will have an effect on you."
She denied charges that her teaching was not good enough.
The school recognised that Mrs Wheeler had a number of difficult and low-achieving children in her class.
Despite these problems, her pupils managed to achieve mainly level 3 and level 4 scores in the Sats in 2002, when most were predicted to get level 2.
"I worked extremely hard to bring out the best in the children in my class," said Mrs Wheeler.
Jim Tindall, her representative, said that she had been off with depressive anxiety on a number of occasions from March 2002.
He said that it was unfair that capability proceedings had been instigated against her, despite warnings that her stress levels needed to be reduced.
Mrs Wheeler requested a mutual termination of her contract in February 2003.
Robert Gilbert, schools link adviser for Sheffield Education Directorate, said he found two of Mrs Wheeler's lessons to be unsatisfactory.
In one, he said, there were "difficulties with the management of pupils".
In the other, he observed "significant shortfalls" in the fundamental skills expected of a class teacher.
Mr Gilbert said he expressed concerns that Mrs Wheeler was given a class with "difficult pupils" when she started working at the school.
The result of the hearing will be announced later.