Dua’a to recite when you are finding something difficult:
Allaahumma laa sahla ‘illaa maal ja’altahu sahlan wa ‘Anta taj’alul-hazna ‘ithaa shi’ta sahlan.
"O Allah, there is no ease other than what You make easy. If You please You ease sorrow."
[Ibn Hibban in his Sahih (no. 2427), and Ibn As- Sunni (no. 351)]