One should recite the following Dua at the time of distress and anxiety
حَسْبُنَا اللَّهُ وَنِعْمَ الوَكِيلُ
Allah is sufficient for us, and He is the best guardian (who takes care) of our affairs.
عن ابن عباس، حسبنا الله ونعم الوكيل، قالها إبراهيم عليه السلام حين ألقي في النار، وقالها محمد صلى الله عليه وسلم حين قالوا: إن الناس قد جمعوا لكم فاخشوهم فزادهم إيمانا، وقالوا: حسبنا الله ونعم الوكيل [آل عمران:173] (صحيح بخاري رقم4563)
Hazrat Ibn Abbaas رضي الله عنهما mentioned that Hazrat Ibrahim عليه السلام recited the abovementioned Dua at the time he was thrown in the fire, and Hazrat Muhammad صلى الله عليه وسلم recited it (this Dua) at the time when some of the people said to him, ‘Indeed, the people (the army of the kuffaar) have gathered against you, so fear them.’ But it (this statement, ‘the kuffaar have gathered against you’ merely) increased them in faith (Imaan), and they said, ‘Allah Ta‘ala جلّ جلاله is sufficient for us, and (He alone is) the best guardian (who takes care) of our affairs.’
Source:Ihyaauddeen