Lolly apart from being male I could have written all your posts 9 years ago. In a nutshell, here is my advice. In the name of God, get out. Get out. Out. You have but one life and there is no guarantee when it will end even if you are in good health. I went into big 4 audit aged 23 post university when more interesting careers seemed sewn up by rich well connected folk. It almost destroyed me psychologically. The very very very worst thing was the disconnect between extended family and others perceptions of my job (ooh sixteen is off to X country with work must be great) and the utter corrosive, sould-destroying tedium of it. There is something else at play. many accountants have frankly personality disorders and cannot ever ever ever imagine doing anything else. In other words you cannot discuss career changes with colleagues because they make you feel it is impossible. I sank into total depression by my late 20s and I swallowed all the crappy lines
"but it is a good job, will you get another one as well paid"
"it will all be worth it when you make partner(zero chance)/earn 6 figures/have a house/nice car"
and my personal favourite
"how will you be able at your age (a geriatric 29 in my case) to cope with the loss of status(yes I really love being depressed and hating my job)/savings/where will you live/are you sure you will get another job when you retrain/do you know how many people 10 years younger than you there are who are prepared to work for no money at all to get into whatever your latest career change"
At this point if you are still reading, I ask that you take a deep breath and imagine putting all your emotions and frustrations into the next crucial, psychological step. What all of these voices, including those which come from your own head, need to do, is to f**k off to the very farthest corner of the known universe. And believe me, they will. They will.
OK I have gone on. I think I may know exactly what you are going through. The house and presumably rent/mortgage is a crucial part of the jigsaw too. I don't want to take up too much space here, but if you want to know how I got out, DM me and I will reply. Life is not perfect now, but I have got to the same level of income I would have been at and yet am in far far better mental health. I was headed for alcoholism and an early death, probably at my own hands, had I stayed on the path you are now on. Much love and encouragement, sixteen.