Why does the questioner feel a weakening of faith despite her consistent devotion to worship and good deeds, and what is the reason for her feeling of pessimism and distress after repeated difficulties in her affairs?

It is advised to be content with Allah's decree, to think well of Him, and to remember that Allah is more merciful to His servants and more knowledgeable of their welfare. He is Wise, All-Knowing, Compassionate, and Kind, and perhaps what is disliked is good, and what is loved is evil. One must continue with righteous deeds, strengthen faith, and supplicate frequently with Allah's Greatest Name to achieve aspirations. Discontent with destiny is forbidden, and neglecting acts of obedience due to affliction is a cause of deprivation. One must ward off the obsessive thought of anticipating affliction and pessimism.