This phrase is a reminder to stay true to yourself and your values. It encourages you to be authentic and to not let the opinions of others define who you are. Always be yourself and don't be afraid to express your individuality.
From Wikipedia
How Not to Kill Yourself: A Portrait of the Suicidal Mind is a 2023 memoir by philosopher Clancy Martin, published by Pantheon Books, which is a subsidiary of Penguin Random House. The memoir documents Martin's struggles with depression and addiction as well as his rumination about suicide including his multiple suicide attempts throughout his life. The book was a finalist for the 2023 Kirkus Prize in non-fiction.