Cancel Zfa training after 8 months?

I started training to be a dental assistant, it was never really my dream or anything, in any case I think it's that bad, my colleagues at work are all good but the boss… especially since I'm a minor they don't seem to adhere to the youth protection law, I'm not actually allowed to work more than 8 hours, but I still have to, and when everything is finished I'm not allowed to leave early, I have to serve the time and that means I always miss my bus and have to wait another half hour, I don't have any free time either, I come home, eat and go straight to sleep, on top of that I've only been there for 3 days, I had a trial day and I worked there for 2 days before the training started and the boss somehow thinks I have to be able to do everything, even things that I've never been told or shown to me, huh? If I do something wrong or if something isn't ready when I didn't even know if it should be there or where the thing is at all, he gets really angry and wants to make me look stupid, even on my first real day of training and on the second day I cried at night, not because I was sad but because it upsets me so much and then I ask what I get no answer