One last entry on doubt and why my doubts about some Catholic teachings have weighed on me.
It is not possible to question or doubt an infallible teaching of the Catholic Church. As an example, here an excerpt from the "Definition" section of Ineffabilis Deus (the document proclaiming the Immaculate Conception):
Hence, if anyone shall dare -- which God forbid! -- to think otherwise than as has been defined by us, let him know and understand that he is condemned by his own judgment; that he has suffered shipwreck in the faith; that he has separated from the unity of the Church; and that, furthermore, by his own action he incurs the penalties established by law if he should express in words or writing or by any other outward means the errors he think in his heart.
To not accept an infallible teaching means you are not in communion with the Catholic Church. This is the same penalty for procuring an abortion or committing murder. It is a serious sin to "think otherwise" about an infallible teaching. I have spent many years studying and trying to understand the teachings of the Catholic Church so that I could accept them; I "craned my neck to Rome" when I was left with utter confusion.
In my exploration of the Eastern Orthodox Church I discovered that the Eastern Church had the same questions as the Roman Catholic Church, but the East answered deep theological questions in a different, thoughtful, theological way (see Doubt and Truth - Part 2). On learning this, the weight of my doubts were lifted.