Nurses are under such pressure that they cannot guarantee safe care for their patients, according to a new poll.
The survey of almost 1,000 nurses found eight out of 10 are under more stress at work than they were 12 months ago.
Asked if they were working under more or less pressure than this time last year, 54% of respondents said "significantly more" and 26% "a bit more".
More than half said they "rarely" or "never" had either sufficient staff or time to ensure safe care for patients, while a third said their ward or team was "always" short-staffed.
The poll was carried out for the Nursing Times.
Asked if their NHS trust was prepared for the coming winter, 45% said they would struggle to provide a safe service all the time and 24% warned that it would be "touch and go".
One respondent said their ward had gone from 38 to 49 beds but staffing levels had not changed.
"Some days I have to stop from crying, because I just feel like I am fighting fires and never make headway in my tasks," the nurse said.
Another, who only qualified recently, described nursing as "exhausting", with every shift "stretched" and nurses "just expected to absorb more and more work".
They added: "I am working several hours for free every week just to try and get everything done."
Overall, 70% of nurses surveyed said it had been "difficult" or in some cases "impossible" to recruit new staff over the last 12 months.
Over half said their team or ward had fewer permanent registered staff than a year ago.
More than half described morale in their ward, unit or team as bad, while a further 22% said good morale was beginning to deteriorate.
Meanwhile, seven out of 10 nurses have considered leaving the profession in the last 12 months due to being overworked and under pressure.
Nursing Times editor Jenni Middleton said: "The story our annual survey tells is a distressing one, because behind the responses about short staffing are tales of care left undone and the risk of patients not being looked after properly.
"It is evidence that in some places finances are once again being put before safety of patients and service users. The simple truth is this - without enough nurses you will put patients' lives at risk and you will consistently fail to hit performance and safety targets."
An NHS England spokeswoman said: "Safe care for patients has to be the number one priority.
"It is vital we are able to attract the right numbers of nurses and other clinical staff where they are needed.
"The NHS continues to work with others including Health Education England to support the recruitment of new and returning nurses, to retain nurses already in post and to help hospitals reach their planned staffing levels."