Answer:
nervousness.
Explanation:
The answer is "nervousness".
Though Bella is studying hard and is studying diligently for the last two months for the exam, Bella is not confident on herself that she remembers everything what she have studied and is nervous.
Bella is under confident that she will forget everything in the exam hall once she starts writing the paper. She also dreams of it. In her dream, Bella also sometimes forgets the way to school.
All these shows that Bella is very nervous for the exam that she is going to give, although she is preparing hard for it.
Thus the answer is "nervousness".
