I think the stress of all the students and professors must combine to form a giant stress cloud over the university and stress storms begin to hit people at random all over campus. No one is immune, I been told by professors who have been teaching for a quarter century that they still have those dreams about missing exams and forgetting class. A friend described the condition as being like post-traumatic-stress disorder, once your body has gone past it's limit of stress your mind plays out irrational scenarios on it's own. I really don't know anything about PTSD but I'd believe that attempting to function in this high stress environment for long periods would begin to effect your health.
In fact, all this stress has helped me discover my end of term mantra; "Just two more weeks, just two more weeks."