First, go before Christ in the Blessed Sacrament and tell him your doubts, fears, weakness. Then, be as patient with Him as He has been with you. When you become aware that He is there, you will be changed.
As to a book, one which reveals God’s love and mercy is the Book of Tobit. It has been called a mini-Job and encapsulates virtually every human experience in it. I much prefer the versions translated from Saint Jerome’s Latin Vulgate, as they are more warm and human. They are in the Douay-Rheims and Knox bibles, both accessible online.