I feel that my heart has became void of belief, how can I restore it and forget this life which has become my main concern?
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu 'alyhi wa sallam, is His slave and Messenger.
A person’s heart cannot be completely devoid of faith unless he has done something to nullify it. The ‘Aqeedah (creed) of Ahlus-Sunnah Wal-Jamaa‘ah states that they do not consider a person who has sinned, even if they commit major sins, a disbeliever, unless the person denies the prohibition of these actions, according to Haafith Al-Hakami.
Ibn ‘Abbaas said that the Prophet, sallallaahu ‘alayhi wa sallam, said that a Muslim is not a believer while committing adultery, drinking alcohol or committing theft or murder. Faith leaves him when he commits such deeds and he cannot be described as a believer. ‘Ikrimah asked Ibn ‘Abbaas, how to restore faith. Ibn ‘Abbaas, told him he can restore it with repentance. [Al-Bukhari]
This shows that faith increases and decreases according to one’s deeds: it decreases by committing sins and increases by repentance and doing good deeds. Therefore, a Muslim has to repent from things that cause deficiency in his faith, do good deeds, accompany the righteous servants of Allaah who can help and encourage him to continue on the right path, and seek beneficial knowledge which leads to good deeds.
Allaah Knows best.
You can search for fatwa through many choices