Am I safe to assume that you are in yr11?
You might want to specify that
And also, by "lost at school", do you mean:
1-you are finding it difficult to understand biology concepts in class or on your own study
2-you are concerned about your marks because you have just completed an exam (end of Term1) and found that you have had difficulty answering biology questions in exams. (and probably combined with difficulty in understanding bio concepts)