Is my teacher mean?

I came into class, and sat down. She told us the classes before us were out of control (That's what I think she said). So she was calling people's parents. All I did was sing a song. I wasn't loud. I was doing my work. Then she called my name, and made me write my mom's phone number. She thought I was talking to someone. I did it anyway. I wasn't going to argue with a teacher and get myself in más trouble. Am I just over reacting....or....Maybe she was having a bad day?