My friends won't leave me alone about my grades and whats best for me..?

Okay so ive been sick and i have a doctors excuse that says i need to go back to school monday. Well my friends keep texting me saying "we have a test today, you should go to school today." I have repeatedly told them no i cant i have a fever and my mom isnt going to let me go to school today. Plus the doctor said not until monday. Then they got mad and said they were just trying to help.. But they arent helping they are making me upset because i know what i need to do, my grades are fine but they seem to think otherwise.. My mom already called my teacher and my teacher is letting me make up the test monday after school. Yes i missed some work but it's nothing i cant handle, now they wont stop texting me and im trying to get some rest. Help!