Hi! Lin Li,
I’m glad to hear from you. Don’t worry too much. Many students have the same problem like you. I think it’s very common for students to be nervous. Here are my suggestions. If you try the following things, you may find you are not nervous and you will concentrate on studying in class again.
First you should relax yourself, and then you can sleep well. Second, you should listen carefully and try to answer the teachers’ questions. It can help you understand better and memories more quickly. What’s more, you also need to review the lessons regularly after class. If you still feel hard to understand, you can have a talk with your teacher to ask for help. I really hope my advice can help you out and pass the final exam.
Keep trying, I believe you will enjoy the school life and make great progress with your study.