Something from Descartes. Paraphrasing from his times, apply yourselves to problems that are solvable, leave the rest to the astrologers. Something I carried with me as an engineer.
Back in the 90s I'd walk through a bookstore and pick up what looked interesting in religion, philosophy and history. On a whim I picked up Mother Teresa'a book and found it a good insight into the nature of suffering and commitment.
There is a lot out there outside of religion.Marcus Aurelius showed that human power politics and intrigue really has not changed much, just the forms. As a Stoic he believed suicide was an honorable way out of a moral dilemma that could not be escaped. Death before dishonor.
Have you read the novel
The Hero, by Somerset Maugham? Or
The Awakening by Kate Chopin? They are both brief and deftly written, and center on the bits above that I bolded. Depressing novels, but true to reality and the sometimes sheer cruelty of happenstance, along with the oppressive moral constraints put on people in society, particularly "polite" society in more old-world cultures. Another great work on the theme of suicide is the short story "Paul's Case" by Willa Cather.
Charles Dickens, George Eliot, Henry James, Thomas Hardy, Nathaniel Hawthorne, Edith Wharton, are just a handful of great English language authors who treated such dark themes.
As for how philosophy has affected my life, it's enough to recite Socrates, via Plato: "The unexamined life is not worth living." The philosophers who have most deeply impacted me are Aristotle,
Spinoza, Hegel, Sartre, and Nietzsche.
Percy Bysshe Shelley is known chiefly as a poet, but his
The Necessity of Atheism is enormous (in impact, not word-count), and he displays a consummate philosophical and scientific knowledge in his copious notes to
Queen Mab. His death at 29 was arguably the greatest blow to the Romantic age; as the death of poet and philosopher/scholar Philip Sidney's death at 31 was the greatest blow to Elizabethan England. Sidney's
An Apology for Poetry is a seminal and important work, touching on far more than poetry.