Secrets of the Interior Life is a little book I picked up at a Catholic bookstore that I did not bother to read until now. I'm almost finished with it and now, I wish I had started it a year and more ago when I was going through such suffering and turmoil. Written by +Luis M. Martinez (1881-1956), Archbishop of Mexico City and Primate of Mexico, it is an excellent book in broadening and deepening our understanding of faith and it's detachment from the sensual, emotional, & temporal. It has given me great insight into understanding the role of faith during those times of great spiritual emptiness and/or spiritual, physical, and mental, suffering. I wish my Spanish was good enough to read it in the language it was written as the translator testifies to the splendid Spanish of it's author but even in it's English translation, the writing is beautifully crafted. Link below to Amazon.com but it can be purchased from numerous sources and is very inexpensive.
https://www.amazon.com/Secrets-Interior-Life-Luis-Martinez/dp/1928832873