50 hours a week is nothing! I was there when the school opened at 6.20am and the caretaker would kick me out at around 6.30pm... and I'd still be taking work home. I'd feel guilty "wasting" time by going out for dinner, or having a bath instead of a shower. It took over my life.
The pressure was immense, both from other members of staff and the parents (mainly the ones who had a habit of shouting at the teachers, because their child would NEVER do anything like that... even though, from the front of the classroom, wearing glasses, you'd seen them do it). Nothing that you do will ever be good enough. I got told off for teaching a Year 1 child to do column addition (she had asked me how to add 'big numbers', and maths was her thing), because, "She's not supposed to learn that until Year 3 at LEAST, and it will put her too far ahead". Oh, and farm words don't count in phonics. 'Sow' is not a word, apparently... it's a female pig, and the child came from a pig farm...
I had 45 children in my class at one point, because the school had a highly transient population (mostly refugees and asylum seekers who would be there one week, and shipped off to live in a different council the next), and was 'very good at dealing difficult children'. There was racism (even from the teachers, particularly towards the Gypsy and Traveller community), staff laughing at the children's names (OK, some were unusual, but perhaps normal in their culture), and snobbery about their families (it was in a poor area of one of the most deprived towns in the UK). You're balancing the needs of a whole spectrum of different children, from the ones who can't recognise the letters in their own name, to the ones who are reading Harry Potter in Y1... plus behaviour problems, EAL, SEN, one who's vomited all over the carpet, ones who have no interest in anything academic (and whose parents thought their child's appearance to be more important than helping them with their reading and things), one whose pet has died and they are inconsolable, some who are hungry because they don't get breakfast at home, parents who couldn't care less about their children's education, children from families where drugs and alcohol and illiteracy were rife, others who were in Care, one who is nervous but excited to be adopted, plus ones that reported abuse going on at home. All of the safeguarding training in the world does not prepare you for 5/6-year-olds describing sexual abuse (and more) in graphic detail. Also, your planning and organisation gets thrown out of the window when it comes to the Nativity play rehearsals, rehearsals for class assemblies, or other special events, which occur with alarming frequency. Then throw in World Book Day and every fancy dress event that you have to take part in.
I ended up buying a lot of things for my (primary) class, including phonics flash cards, fruit, underwear and socks. A chunk of your evenings and holidays will be taken up sorting out your classroom, organising and planning lessons and activities, and worrying about what sort of home some of the children in your class are going home to.
By the end of it, I wasn't sleeping, rarely ate, and was having issues managing my own personal hygiene. I had a nervous breakdown, left on sick leave, and swore that I'd never teach anyone anything, ever again. I'm really glad that I got out, although I do wonder what happened with some of the children in the end. Either way, I hope that things worked out well for them all.