McDonald's

I am a 15 year old who has worked at this resturant for 11 months now at first evrything was good but now my manager has been harassing me I go to school in dance and cheerleading they knew all this when i was hired and now they schedual me to work when she knows i am not available she denied me my availability and told me i have to come to work ive had to go to my dr because i am so sick all the time all i wanted was a couple shifts a week I need someone to help me I dont know how much longer I can go on like this my parents are worried sick because she gets me so scared im in tears and sick so much..someone help i dont know who i can talk to