Zoloft and other anti depressants need to be taken consistently to work properly and can be very dangerous if not. I am glad you took that into your own hands and make sure she gets what she needs each day. (and maybe remind her, that just like high school, it won't be for forever).
As for the money, I agree with everyone else. I never got paid to do chores around the house. By 17, I had already held a job for two years working 20+ hours a week, went to school and had a 4.0 gpa, and came home on my off hours and after school before work to care for my mom who had leukemia. She needs to be prepared for the real world and nothing is free or handed to you in it, sad to say.