Mother Teresa's dark night of the soul

From Mother Teresa's letters (April 1961):

"Now Father - since '49 or '50 this terrible sense of loss - this untold darkness - this loneliness - this continual longing for God - which gives me pain deep down in my heart -

Darkness is such that that I really do not see - neither with my mind nor with my reason -

The place of God in my soul is blank - there is no God in me - when the pain of longing is so great -

I just long and long for God - and then it is that I feel - He does not want me- He is not there - ... God does not want me -

Sometimes I just hear my own heart cry out - "My God" and nothing else comes - The torture and pain I can't explain."