To clarify, what doubt actually has to do with is trusting God, not teachings about God, not the existence of God, but God himself. To not live in fear or distrust, including of doubt.

The real problem is the Catholic Church decideding Doubt is evil. Indeed, doubt is a major part of "carry your cross and follow." (Luke 14) Christianity is not easy - you face some combination (different for every sinner) of persecution from the outside and psychological terror from within, both from within your soul and from within the church and its many false prophets and hypocrites. I would point out that the meaning of "faith" has nothing to do with unquestioning belief, though some degree of that may be necessary to get anywhere in anything from Christianity to Mathematics. It is also, however, immensely rewarding. My mind has been spectacularly expanded since I followed, my relationships have deepened, my character has grown full and rich. Even my very scars, bleeds, and bruises I consider a mark of pride. Thanks be to God!