I also think you should tell her face-to-face. If you don't, you are still letting her control you, in a wierd way. You can be honest without telling her everything. If you put everything into an "I" statement, she can't really argue... "I have given this a lot of thought... I feel really torn... I'm just not happy working her any more...I have decided... I'm noticing that you are trying to talk me out of this.. etc." Make your decision, and don't argue. If she tries to argue with you or talk you out of it, just sit there in silence at look at her. Nothing more to say.
You shouldn't worry about upsetting the boss that is making you miserable. Quit so you don"t have to be miserable anymore. So you don"t have to worry also about upsetting them when you quit. Give 2 wks notice. Say something like it doesn"t fit your schedule or you are going back to school. And if you don"t think about it it can"t upset you.
i wanna quit my job and be lazy for a month lol but i can't i need the money
No you need to talk to her face to face. If you email her then she will get upset. She will try to get you to stay because you are obviously a big contributor but just tell her the truth. If she insists, tell her to give you time to think it over but that you are definitely giving her notice in writing.
I know it s a tough thing to do and you might feel a bit of a traitor but let me tel you, if she had to let you go because she has to tighten the budget, she probably would - she is running a business.