Is the intense distress that only disappears during prayer, and the inability to lead a normal life due to a son's illness, considered a weakness of faith or forbidden, or is it a natural feeling?

Contentment with divine decree is a cause for happiness, and it does not contradict sadness and pain over calamities, as long as the heart is at peace and not resentful. It is not a condition of contentment to not feel pain and adversity, but rather to not object to God's judgment. There is no contradiction between the existence of pain and contentment; the patient's contentment with bitter medicine, the fasting person's contentment with the heat of hunger and thirst, and the mujahid's contentment with the pains of wounds are examples of this.

A servant should not surrender to excessive grief that leads to negligence in duties or weakens the heart from performing what God has commanded. One must strive against oneself with patience, live with one's spouse honorably, and entrust matters to God, with the certainty that all of God's decree is wisdom and mercy, and He decrees for His servant nothing but what is good for them. "And perhaps you dislike a thing and it is good for you; and perhaps you love a thing and it is bad for you. And Allah knows, while you know not." One should also strive to acquire the means to increase faith and broaden one's chest.