I recently had retire from teaching on ill health grounds. I was physically burnt out due to my excessive workload and a number of medical conditions, which I had previously successfully managed, flared up. On top of my already very heavy workload, I was covering the remits of two other teachers, who had been seconded to other schools, due to staffing problems. Working till after midnight most nights, trying to cover paperwork, as I spent most of my day dealing with behaviour and children who had social and emotional difficulties was the norm. I was promised that it would only be for 3 weeks, till the situation was resolved. Six months later I was still doing it, as "No one else was experienced enough to manage these children." said the HT. The school I worked in was in an area of great deprivation. On going for a routine hospital appointment, my consultant would not allow me to return to school, indefinitely.
As for long teachers' holidays, I spent most of mine in school, installing new ICT equipment, whilst the school was empty and preparing lesson programmes, ready to to be given to staff on in-services days. I loved teaching, just couldn't find time to teach! It is not the job I signed up for and it nearly finished me off.