I don`t speak Norwegian, how to cope in class?

Hi, I have lived in Germany since I was three years old because my dads job here. This summer we moved back to Norway, but I don’t speak any Norwegian. My parents never thought me Norwegian when I was living in Germany, they only spoke to me in German and I learnt English from going to an international school. I am now going to ungdomsskole in 10th grade, but it’s been a month now and I still don’t speak any Norwegian. I don’t have any friends either, because I can’t talk to anyone. My dad is always away and my mum says that I will learn it eventually. Every day I am just sitting in the back of class listening to the teacher talking but I don’t understand anything. In most subjects I am not doing anything, I am just sitting there for an hour doing nothing. In English class and German class I get to do some tasks from the book, but I still don’t understand when the teacher is talking. I don’t understand what to do, my family don’t care, and I still miss all my friends in Germany :(