When the heart feels heavy with anxiety or sorrow, the most sincere refuge is in God’s remembrance and supplication. Among the Prophetic prayers:

• Supplication for distress and sorrow:
  "O Allah, I seek refuge in You from worry and grief, from incapacity and laziness, from stinginess and cowardice, from the burden of debt and the oppression of men."

• Supplication in hardship (Dhu al-Nun):
  "There is no deity except You; exalted are You. Indeed, I have been of the wrongdoers."

• Remembrance during trials:
  "There is no deity except Allah, the Most Great, the Most Forbearing; there is no deity except Allah, Lord of the heavens and the Great Throne."

For peace of mind and reassurance:

• "O Allah, I seek Your mercy to soothe my heart and remove all distress."

• "Take me from the tightness to the widest path, relieve me from overwhelming hardship, and remove every difficulty from me."

• "O Allah, grant me peace of heart and mind, and bless me with happiness in this world and the Hereafter."

Dhikr for calm and serenity:

• SubhanAllah, Alhamdulillah, La ilaha illAllah, Allahu Akbar.

• "Indeed, in the remembrance of Allah do hearts find tranquility." (Quran 13:28)