The Consolation of Philosophy by Boethius. Written in 523 while he was imprisoned and awaiting execution by the Ostrogothic King Theodoric, it is often described as the last great Western work of the Classical Period.
As a person who's gone through something comparable in recent years, I will first recommend that you seek out a community of people undergoing a similar shift in worldview. There may be podcasts, forums, blogs, etc. where people who previously held your same worldview are processing their transition after finding "that a lot of the things that [they] used to believe were false". For me this has been immensely helpful. Now some introspective books: * The Mistborn Trilogy by Brandon Sanderson. If you're open to fantasy, this series delves deep into how to respond when one's worldview is shattered. Highly recommended. Elantris also covers some similar territory. * The Consolation of Philosophy by Boethius. How do you reconcile the whims of capricious Fortune with your desire for peace in this world? * Bonds That Make Us Free by Terry Warner. This book makes you take a brutal look at how you contribute to your own misery in life. It will be agonizing to read, but persevere and I believe you will find it insightful. Try not to be too turned off by the conservative religious viewpoint that occasionally peeks through.
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