Q: Please what is the cause of sadness, torment, unhappiness and depression in the life of a Muslim?
A: There can be many reasons. The better thing for you is to keep in touch with some righteous pious buzurg. He will be in a good position to guide you. In the meanwhile see that your namaaz are performed on time with calmness and ease and don’t have hopes and expectations with people and things.
And Allah Ta’ala (الله تعالى) knows best.