A woman's life was turned "upside-down" when major surgery was cancelled four times by a hospital suffering from extreme pressures.
Katie Flack had already been prepared for surgery when the Royal Cornwall Hospital cancelled her hysterectomy.
The hospital declared the highest alert - Opel 4 - on more than 130 days in a 12-month period.
Dozens of hospitals across England also declared the level, something unions described as "horrifying".
In a statement, Royal Cornwall Hospital apologised to Mrs Flack and said while last winter was "particularly difficult", the decision to postpone an operation was "never taken lightly".
Mrs Flack, 30, from Pool, Cornwall, suffered from a painful condition called endometriosis, in which tissue that is supposed to line the inside of the uterus grows on the outside.
"I went through everything the doctors threw at me and nothing worked, so in the end they told me that I needed a hysterectomy," she said.
'Prepped and ready'
On 22 January she "went into hospital and sat there for the majority of the day" before her surgery was cancelled because of emergency measures.
On the second occasion, Mrs Flack was in a hospital gown, "prepped and ready for theatre" when it was cancelled again.
Twice more the surgery was scheduled and cancelled.
While she praised the "amazing job" done by NHS staff, Mrs Flack said it felt like bosses did not realise the effect surgery cancellations could have on mental health.
"Having such a major operation at such a young age, it was already a massive thing and worried me since the day they said I needed one.
"You psych yourself up for it, and then to be told you're not having it done - I just cried for 24 hours afterwards."
Mrs Flack said her son has learning disabilities and needs a steady routine - something that was not possible during the months around her surgery. She had four operations scheduled and cancelled before finally having her hysterectomy in March.
"We had to prepare him every time for mummy to go in for an operation which completely unsettled him and turned his life upside down. We had to do that five times," she said.
The Operational Pressures Escalation Levels (Opel) are designed to bring a nationwide consistency to the way hospitals handle a crisis.
While the framework applies across the country, some hospitals have told the BBC they feel elements of the language are subjective, and that interpretation of the different Opel levels could vary from trust to trust.
Opel 4 is the highest level, declared when a hospital is "unable to deliver comprehensive care" and patient safety could be compromised.
In the year leading up to September, Royal Cornwall Hospital declared 134 days on Opel 4 - the highest in England, according to responses to Freedom of Information requests sent to all hospital trusts. Just under 70% of NHS trusts responded to the BBC.
The trust was rated as "inadequate" during the Care Quality Commission's last inspection in June and has been in special measures for more than a year.
Elsewhere in the country, one senior NHS nurse told the BBC last winter was "the worst in 20 years" and working in escalation areas was "absolutely horrendous". Patients did not get the treatment they "need and deserve", they said.
The GMB - one of the unions that represent NHS staff - described the figures as "horrifying".
Union official Rachel Harrison said the health system was "stretched to breaking point" after "almost a decade of cuts".
"Our members have to work under enormous pressure - desperately trying to save lives while they are short-staffed, under resourced and under worked."
The Royal Cornwall Hospital said work-related stress had come down by 10%, and it had new plans to "create improved and integrated care".
The trust in Leicester said it was the "busiest single-site emergency department in the country" and the "last 12 months have been busier than ever". Great Western Hospitals said the figures "may seem initially alarming" but added that it was expanding its emergency department.
NHS England said it was crucial local health services and councils "co-ordinate their response to winter pressure".
The Department for Health and Social Care said nearly 15,000 fewer people were waiting over a year for non-urgent operations compared with eight years ago.
It added it had given the NHS £2bn this year to improve performance, redevelop A&Es and help patients get home quicker.