You have been given some great advice and really one amazing story. Here is something else to ponder, the beautiful thing about being Catholic is being Catholic. Sounds stupid really but it is not. Catholic as you know means Universal. In other words you have some options, of course one is the one you suggested and that is leaving the Church and Faith altogether, but before you do that try a new Parish. You didn't mention doing that. You did say that you look around you and see just as many spiritually dead people. I am taking that to mean people in your Parish. Try a new Parish. I swear I have encountered Priests who have no business serving in Parishes. Much of this has to do with the lack of vocations of course. Many of the bad priests I have met are fulfilling roles that they themselves don't want to do. And believe me like in any job, if you don't like it ,it shows.
Next step is bringing yourself up spiritually and nothing mocks the devil more than humor. If you have never read C.S. Lewis' "The Screwtape Letters" than pick up a copy today. I think I've read it a dozen times. And someone wrote "to remember what attracted you to the Church in the first place". Well what was it? And if it isn't there in your Parish anymore I bet your bottom dollar it is somewhere.