Tom had convinced you to keep you both in a secret. He denied he could feel anything for his so-called "enemy," but yet he kept coming back to you

One day, you were walking to Potions, not so far from you, Tom walked along with his few friends, who were shit talking you. It didn't really bother you until Tom spoke

"She's a loser, I don't wonder why she has no friends"

Those words hurt you because they came from him, you just walked past him, making him notice you