the last straw

I wasnt 1000% sure when i posted my last post about me leaving September, but now I just feel it makes sense and I doubt ill have any serious regrets. I booked a day off for today, I'd booked it in April. Today my boss phoned and said my day off was cancelled, he needed me to work. So i had to work despite my moaning. My plans had to go out the window. During teaching a 4 year old boy I asked him if he was happy. His reply was quick and non-hesitant. "No, I am not" "Why?" I asked. "楽しくない." I agree. With the materials I am allowed to use and the things my boss has told me off for doing when I try and spice things up, Im left with nothing to do but to bore the poor kids to death until they die and quit, and then my boss can moan at me and duck my wages. ...But I have tried my honest hardest to do this job, a job I dont know how to do.

Today with everything that happened was the last straw. Probably going to quit end of July. Cant afford to quit before.

Its not fair on the kids and its not fair on me, the amount of stress that gets piled on.

If I had a nicer job, I might be tempted to stay, but....

I just cant hack it any longer.