What is something that makes you feel sad but can't tell others?

Thank you for coming back to me, really! Suddenly I remembered what happened when I was a child in elementary school. At that time, I always made mistakes when doing math questions. The teacher stipulated that once I made a mistake, I would tear up the notebook. I kept changing the notebook and rewriting it and handing it in again. If I didn't have any pocket money at that time, I would borrow it from my classmates. Yes, because I always asked someone to borrow money, I was embarrassed to ask her again, but I didn’t expect this girl to lend me money again. I was already prepared for him to reject me, so I borrowed the money and I was ecstatic and happy. Relieved, I ran across the aisle to buy homework books. At this time, from the corner of my eye, I could clearly see a boy moving from the position against the wall to the position near the aisle, but all I thought at the time was "I'm so happy." , he lent me money again, so I can buy a book.” In this way, I tripped over that boy, and when I fell, I hit the wall with a heavy sound. I’m scared to think about it now, probably on TV. That's how I hit the wall and committed suicide. Now I can't remember how painful it was. When I reacted, I still thought "I'm so happy that I finally lent me money. I can buy a notebook." With this thought, I quickly ran out of the classroom. I went to buy a notebook. Maybe the teacher was too terrible. If he didn’t have a new notebook to write his homework, the consequences would be serious (corporal punishment was very common in my elementary school. It was common for the teacher to stretch his hands with a stick and slap him). I didn’t even argue with the boy. I got up and ran out. It’s 23.44 on March 14, 2017. It’s very sad to think about it and I want to hold the same me.