It's Overwhelming

I literally don't want to go to dance classes anymore. I have them twice a week... After school and Saturday, in the morning. I wanna catch up on some sleep mother, I waited for this week end for what? To go and work again? It's the only time I have chances of having free time but even that gets taken away from me. Got yelled at just now as well for asking if I could go to dance classes once a week only. I also have math and chemistry tuitions. The expectations are very high and I can't bring myself to do any work. What's the point? I do a lot but nothing changes. My grades are still down the drain. My mother lets me (and forces me) to do things that only benefit her. I went to guitar classes but she stopped them and said that I can only go back to them only if I get good grades in every subject (impossible). And yet, she still gets super mad when I don't play my guitar that I got for my birthday, she didn't pay for it. What's her problem? And yeah how can I play guitar if no one will teach me? I don't like being self-thought. And when I'm not having tuitions, I get told to study and she takes away my phone, laptop and wifi priveledges. She uses my converse (I love them a lot) to manipulate me. She hides them when I "misbehave". I found all her hiding spots anyways. She also shames my body. "Other girls your age don't have stretch marks!", shut up... Just shut the fvck up. You never saw because they don't show it. And at least their parents don't touch them inappropriately.