"Fresh Air" by Chris Hodges was exactly that for me - a burst of fresh air into my mind and heart. I think it's normal to have a blah period of life or even serious or situational depression - and if you are in that circumstance or have ever been there, you will get a lot out of this book.
We are taken through three stages: 1) Searching For a Breath of Fresh Air, 2) Bringing Fresh Air Into Your Life, and 3) Finding the Source of Breath. From his personal experience of 'the doldrums', each chapter begins with relevant quotes, has great content in the middle, and ends with 'breathing lessons' - practical direction, and Bible verses that are relevant to the chapter.
There is quite a bit of Biblical content and it never feels forced or dry - just breaths of Fresh Air that so many of us desperately need. This book is a great encouragement for anyone who asks the question, "Is this all there is?" (Nope. There's more.) :)