I think that an instructor should be a little tough sometimes and they definitely shouldn't baby you, but that is completely ridiculous.
I went to a barn for ten years and did everything for my trainer. I couldn't afford lessons, so I ended up working for what the lessons were "worth". In the summer (since I'm only a teenager and didn't need a job two years ago) I'd show up at the barn four days a week, clean 4 paddocks in two hours, clean all the water troughs and refill them, clean the stalls, clean the ring (because she kept one of the horses in the ring when it wasn't being used), trim the bushes that were overhanging into the ring, dust the barn, throw the hay down, help the new kids with tacking up and cleaning, clean all the horses (including the sensitive, spooky one that took 45 minutes to catch from the paddock. I swear, the horse came to us naturally sensitive and sweet, and that woman soured him so that he had to be sent back) and then I'd go over to the other barn she was in charge of and do it all over again. I went over to the barn three times a day one week to take a sick horse's temperature while she was away. Does that sound like it covers $60 an hour?
The only time I got to have quality lessons in which I learned something was when I rode with one of her rich summer clients, a nice but clueless girl that would take up 15 minutes of the hour that I worked so hard for that came around once a week by putting on her half chaps backwards -.-
It was infuriating to me, because this rich girl could just buy more lesson time. I couldn't and there she was giggling at herself as she took another 10 minutes to try and figure out how to put on her own equipment. On the times that I didn't ride with her, the "lessons" were short and basically consisted of me trotting around the ring, occasionally switching direction out of boredom while my trainer did stuff on her phone, almost completely ignoring me. I was essentially just exercising the lesson ponies.
I left that barn after my friend and I, who again she's known and trusted for ten years screwed up once in our entire time there. My friend sat on the bombproof, 22 year old push-button lesson pony with no tack and helmet while I cleaned the paddock. We were just talking, the pony was standing in the shade, completely uncaring and my trainer's mom pulled in (she lives on the property), saw us, and my trainer called me and screamed for about 6 minutes. I was called a dumbass, an idiot, stupid, who did I think I was, what did I think I was doing, she's going away for a few months and already I've screwed up, yadda yadda yadda. Then she called my mother and told her that me and my friend skipped school to go ride the horses bareback. The way she described it made it sound like we took the whole herd out for a gallop with no tack or helmets into the road. Needless to say, it completely shattered my self confidence. I went to school the next day having severe anxiety attacks, I threw up once, and I cried for 6 hours straight all because this woman who I trusted and respected had belittled me in a way that I'd never even experienced. I went back to that barn once to get my stuff and say goodbye to the horse that I'd had an attatchment with and never saw it again. The experience also destroyed my confidence as a rider, now when I occasionally ride, I know I'm horrible. The worst part is, I was only 13... What 13 year old doesn't make mistakes? When my mom found out how this woman had screamed at me (which she failed to tell my mother when she called her), she was very angry and told her that her response was inappropriate. Nobody was even close to hurt, the situation frankly wasn't that dangerous. So I'm surprised that your parents just sit back and take that...
Lol so the point of this huge long story is, get away from the things that are bad for you. I got away from my trainer and now am worlds happier. There's no way you're going to improve as a rider and as a person with a trainer like that screaming horrible things into your ear. Don't believe any of it.