This is probably not where to ask but I couldn't think of anywhere else

I'm looking for a webtoon (not sure if it was bl but I don't think so?) It's really short, ten chapters I think. It's about a girl who transfers to a new school and is very lonely. She find a letter glued under her desk that leads her to other letters around the school. Through the letter she meets a boy who knows who wrote the letter because he used to be his friend and is mad at him for leaving without saying anything or something like that. In the last chapter I think they meet the friend who wrote the letters. Gosh if anyone the name pls let me know ╥﹏╥