Would this be considered child abuse?

Friday I brought home my report card and I got a C. Grades are a biggggg thing in my family. A couple days ago I went to the doctor and they said I have bad bronchitis; I can't stop coughing. My mom is soo mad about my report card that she took my antibiotics and will not let me take the rest. I have only taken 2 so far out of 5 days and I am really sick. I don't know what to do. I know it is my fault for getting the C but can someone tell me how else to treat the bronchitis? I am 16 so I know I am kinda old to even be asking this but I just really dont know what to do.