Periodical Exam

One of my most hated things about school,PT. I mean Not only it is hard, it makes me hungry, it makes my head ache , it keeps me awake until late at night, not only that it is long! Before the examination days our teacher in chem told us that if we will get a low score in the PT our parents will be called!What should I do? Well, I studied and I am sincere when i said I STUDIED. Well I think I answered the questions wholeheartedly but I did not finish.And it makes me so nervous. I answered the pt for I hour and 30 mins. But still I didn't finish. What if my parent got called. My mother will sure kill me. I don't know what to do. I am getting crazy just because of chemistry, a science subject. And I have other science related subjects, I will sure be crazy.