Late for a Test in an Empty Old School Meaning & Interpretation

"In my dream, I walked into my old school. The halls were long and empty. I looked at my watch and realized I was late for a test. My heart started to race. I ran to my classroom, but I could not find it. Every door looked the same. I opened one door, but the room was full of strangers. I opened another, but it was completely dark inside. Finally, I found my classroom. Everyone was already writing. I sat down quickly and looked at the paper. The questions made no sense to me. I had not studied for this test. My hands began to shake. The teacher looked at me with a serious face. She said time was almost up. I tried to write something, anything, but my mind went blank. I felt small and scared, like everyone was watching me fail. I looked at the clock. It was ticking faster than normal. My chest felt tight. I wanted to explain that I was not ready, but no words came out of my mouth. Just as the bell rang loudly, I woke up. My heart was still pounding, and I felt relieved it was only a dream."