This is a real-life blog, so maybe not quite a story, but...
The Fiercest Invalid
This blog is written by someone who detailed her thoughts prior to and on the day of her suicide. In her own words, "
The following is a collection of journal entries and personal reflections assembled over the final days of my life."
What really astonished me about her is how determined and unwavering she was in her desire to die. Her last blog, where she said her final goodbye, was posted November 20, the very same day she committed suicide (There's an obituary for her); she went through with her plan with no hesitation, not hindered by survival instinct whatsoever.
This didn't necessarily make me cry a waterfall and all, but reading about her pain, her hatred for herself, and, perhaps the saddest, her overwhelming love for her family and friends, really stuck with me for a while after. Hell, I first came across this blog in December 2017, and I still think back on it from time to time. It's a very powerful read, especially to someone who shares her thoughts.
Edited to add:
This Reddit post includes her father's response to her suicide, which was especially heartbreaking. (It used to be on Facebook but can't be found anymore).