Exam - is it stress?

30 years ago I graduated from my Marine College.
    And for all these years, every 2 - 3 Months I'm dreaming a terrible night dream, when sleeping at night. I see as I come to Harbour Master's Office and they say that I forgot to pass a few exams in the College. So my degree is not valid and that I now have to take the exam together with the cadets.
  And the missing items are something like the theoretical mechanics, strength of materials, TSS (the theory of the gyroscope). And I'm
terrified in a crowd of current students whip for consultation before the upcoming exam tomorrow.
   What is this? Do exams in high school are such a stress, which has an impact for life time?
  Very strange. I was never afraid of examinations, often I did  first and without written preparation, to give fellow cadets more time to prepare an answer. So, seems there were no stress, or whether it was on a subconscious level?
   I do not know.
   And do you have the same recurring dream for years?