Recently same thing occured in my dreams. I dreamt I have the math exam, and I cannot answer any questions on the test paper. I am very nervous for it's time to submit the paper, however, my paper is still blank.
I have a poor quality sleep for such a dream. Math subject is my strong point in my school days, now I couldn't answer a question. How could I calm down? In the dream, I thought maybe it was because I graduated for several years then I forgot all math knowledge. I show pitiful facial expression to the teacher who comes to collect my paper in order to get some forgiveness from her.
I find I will have such dream after I study hard English every night. Maybe in my subconsciousness I am afraid that my English is worse than my colleagues'.
I already stepped into society, to be honest, I have no any skills to support myself, I just know more English words than some of my colleagues, and I depend on these English words to get my salary each month.
So I need to try my best to learn English, if not, I am really good for nothing.