I hope you won't mind if I chime in here, because the OP raises some questions that I have asked myself during my search for (and confirmation of) my Christian faith.
About myself: I was raised Anglican, baptised and confirmed Anglican (many years ago) and I was blessed with a musical talent that has led me to worship and praise with many different congregations, from Catholic to Pentacostal and all across the Christian spectrum in between (b/c I've played professionally for many congregations, for holiday services or other special occassions like weddings etc.)
Your post caught my eye, because you wrote, "I find it hard to accept that the Catholic Church would have so many people behind it if it weren't true. Any help?"
I'm not sure if this thought would be of any help to you, but it seems to me that you might be troubled or struggling with an "ad populem" approach to your faith...that is to say, "so many people" believing in such or so a way (a popular way, that is) might be leading you to believe that another way (e.g., EO) is not "true" because it is less popular?
I hope I'm not rambling, but I think I have an understanding of what you mean. For me, I am drawn to Eastern Orthodoxy because I sense a purity of thought that underlies its expression of faith. I'm not sure how to explain that feeling, other than to say that even though I'm aware that EO is not "popular" in the sense of Western Orthodoxy, its popularity is not my concern: what I seek is a firm basis for my own faith, which I seem to be finding in EO.
Forgive me if I've rambled too much or posted inappropriately; I'm new here, and I was just trying to express how I would approach that question.
Blessings!
D