TIME has a fascinating and must-read article about Mother Teresa's own struggle with faith and her total belief in God. It is a shocking view into her spirituality during the last half-century of her life.
In essence, her letters from the time she began her ministry to the poor until she died, reveal that she was tortured by “such deep longing for God,” and that she felt “repulsed, empty, no faith, no love, no zeal.” She says she wanted to believe so badly, but just couldn't feel God within her soul.
The mainstream media will run with this, implying that Mother Teresa was a fraud and a hypocrite and how can we believe anything she said or did now. Non-believers cannot possibly understand the worth of self-sacrifice. My take, and the theory I choose to believe, is that the torment she felt in longing for a true presence of God, was the sacrifice and test given to her by the Lord. Kind of like Jesus' proclamation on the cross, "My God, my God, why have you forsaken me?" This proves that we are all human and have our moments of doubt and question. Perhaps this was the cross God gaver her to bear. Many saints have gone through dark periods of their life. The fact that they continue to perform great works despite feelings of faithlessness, is perhaps one of the great reasons they are called saints.
Please check out the article, and then do some research yourself on saints. Many of them led very fascinating lives that we can all learn from.