Doubt is not the opposite of faith; it is part of the human condition under faith. What the tradition distinguishes is involuntary doubt — the unsettling feeling that one's beliefs may not be true — from voluntary doubt, which is a wilful rejection of what has been established. If you are here, you are likely suffering from the former: the kind of doubt that arrives unbidden, that disturbs rather than liberates, that leaves you feeling spiritually unmoored. This form of doubt is not a sin. It may even be, as several of the Doctors of the Church have argued, a form of grace: the death of a faith that was too comfortable, too cultural, too based on feeling rather than conviction.
The Catholic intellectual tradition is the richest in Christian history, and it is extraordinarily well equipped to handle objections. Augustine was a sincere seeker who spent nine years among the Manichees before conversion. Thomas Aquinas, in the Summa, begins every article by presenting the strongest possible objections to Catholic teaching before answering them — the greatest act of intellectual honesty in theological history. Newman converted late in life after exhaustive historical study. Chesterton was a young agnostic who reasoned his way to orthodoxy. Scott Hahn was a convinced anti-Catholic seminarian who read his way to Rome through the Bible alone. You are in distinguished company.
The books here work at different levels: some are emotional and existential (Augustine, Merton, Lewis); some are rigorously intellectual (Aquinas, Chesterton); some are personal accounts of the journey from doubt to conviction (Newman, Hahn). The sacramentals recommended are not for those who already believe easily — they are for those who need something physical to hold on to while the mind works through what the heart is not yet sure of. Begin with what matches your current mood, not with what seems most respectable.