Young people - teenagers especially - find themselves in the situation of this boy all the time: stressing over what's next and what's to come. Many times, it is all drama and every test, every encounter seems like it is life-changing - or life-ending. The video illustrates the value of prayer - whatever form that may take. The Jesuit examen is a great one, particularly for young people. It gives a sense of perspective that can help us recognize what is first, what is next, and what is important. The teacher is right: it won't help you get an A, but it will help.
One of the gifts that adults have to offer is perspective. When I was training for priesthood and thought that I had screwed up royally, a supervising priest once said, "Did anyone die? Did anyone lose their soul?" Of course not. It was a learning experience, and I gained some perspective myself. Our youth lack that, and it is responsible for us adults to help them with it. Prayer is the spiritual sense of perspective for those who avail themselves of it.
So calm down; place your feet flat on the floor; and pray.
It won't do everything for you, but it can't hurt.