Lack of faith can mean many things: losing trust in God after a hardship, feeling that prayer is empty, doubting that our efforts matter, or simply finding belief hard in a skeptical world. It can be lonely, especially if everyone around seems certain. Many sincere people go through such seasons, and they often come out with a faith that is more honest than before.
The Gita treats faith as something that grows through practice. Gita 4.39 says faith, sincere effort and mastery over the senses lead to knowledge and lasting peace, so belief works best when combined with disciplined practice. Gita 4.11 says the Lord responds according to the sincerity of one's approach. Gita 4.3 says divine wisdom is revealed to those who approach with devotion, trust and sincerity, and Gita 17.28 warns that effort without faith accomplishes little of real value.
Faith does not need grand conditions. Gita 9.26 says a leaf, a flower, a fruit or water offered with love is accepted, so begin with what you have. Gita 11.54 and 14.26 point to wholehearted, steady devotion, and Gita 12.20 praises those who live these qualities with faith in everyday life. Make a small daily practice, give it sincere attention, and treat faith as a path to practise, not only an ideal to admire.