I hid my best friend's s*icide letter.. I don't know what to do

One year ago my best friend of 2 years committed su*ide it was a shock her parents were broken so me and another friend volunteered to clean her room under her bed I found the letter she left I put it in my pocket and when I got home I read it the letter was horrible she wrote that she hates her life and her family and she regrets that she was born I folded the letter and put it in my closet I never told anyone

I know I'm a bad person because one of the things that hurt her parents the most was that she didn't leave a letter but I couldn't let them read it I think about it every day since

(sorry for bad english, not my first language)