Is feeling despair, sadness, and fear, despite drawing closer to God and memorizing His Book, considered a sign of lack of faith?

The upright Muslim's entire affair is good; if prosperity befalls him, he is grateful, and if adversity befalls him, he is patient. He should not grieve or despair, because despair and hopelessness are associated with disbelief and misguidance. Allah Almighty says: "And do not despair of the relief of Allah. Indeed, no one despairs of the relief of Allah except the disbelieving people," and He says: "And who despairs of the mercy of his Lord except those astray?" When sadness or fear creeps into the heart, the Muslim should find reassurance in the remembrance of Allah and supplicate with the prophetic supplication: "O Allah, I am Your servant, son of Your servant..." He must also observe the obligatory duties and supererogatory acts, and avoid what displeases Allah Almighty. Allah Almighty says: "Whoever does righteousness, whether male or female, while he is a believer - We will surely cause him to live a good life."