After a person spends a great deal of time *away *from religion, *returning *to it again can seem a bit as if you are stepping through Alice’s looking-glass. That is, our reason can often find religion to be a bit of a shadow-world, where there are shades and nebulous realities; and entering into this world is something which our reason will often question, and will make us feel as if we are mistaking sense for madness. A solution to this, as another poster has alluded to, is to train your reason to view such a shadow-world in such a way that you find therein solid ground and that you ‘see’ its contours and are able to manoeuvre within them. To put it simply, if you *wish *to find religion reasonable, you *will *be able to do so, given enough time. This is especially true of Catholicism, which is ancient, and which was the foundation of post-Roman European society, and which has experienced a great deal of defending from some of the most brilliant minds of the West. To believe in such a thing is easier, than it is to believe that John Smith who lives down the lane is a prophet of God.
The ‘fizzling out’ you experience, can be explained in many ways, the most obvious being that the excitement of religion loses its potency after a mere bit of time to a great deal of people. Others have told you what you can do to overcome this obsticle; that you should immerse yourself in the society of Catholicism, so that you have company, and certainly, if I took you to the Cathedral of Milan, its beauty would inspire you for a time to be an entirely devout Catholic. Again, if you *wish *to find excitement, it is there to be found, if only you look for it, and are willing to immerse yourself in it.
But what I should like to offer to you, is the advise that you should examine why, precisely, you *wish *such a thing as Catholicism in the first place. You appear to feel as if you ought to be Catholic, but for why? What do you fear, what do you lack, and what will you benefit from this religion? Perhaps it is so that you can meet a lot of such needs in more mundane ways, so that, by removing such needs, you might test your spirit to know whether what it feels you require is what it requires in truth.
The things that we chose to believe, are the things which we will find reasons to believe, if only our will is strong enough, and we arm ourselves with the proper resources. But before such a path is embarked upon, know where the path will lead you, and why it is you wish to arrive there.
If you are certain that you desire to live each day as a believer in Catholicism, or any other religion, than begin your daily regiment of immersion and study. Immerse yourself in the religion, so that it becomes familiar, and therefore more real. Study those authors who defend the religion, builing up your own reason to view (what now appear to be) shadows as living bodies. Lastly, for a time, ignore attacks against it; utterly close yourself off from any sort of external logic. Above all, ignore other religions, and do not study them on their own terms, for when one understands why others believe in what you might perceive as folly, one will be less prone to not see all religions or paranormal or esoteric belief as folly.