I need help with iTunes Match.

I have built up a very large iTunes library. I have all my songs on my iPod classic, and used to have them all on all of my devices, but now I only have them on my iPod classic. This is because recently I started using iTunes match. I want a flawless, fully synced library, but at the moment different parts of my library are sitting in different devices. I have a MacBook Pro, an iPhone and an iPod Classic, and some of my songs are on my old PC. I am syncing my iPhone between my two different computers, and each time the result is different. I have 3 seperate libraries, on my Home Sharing, one is My iPhone. One of the libraries is from my old pc, the other is from my new MacBook. I also have a lot of duplicates. I am afraid of syncing my iPod classic with either of my computers for fear of losing everything. Can anyone please tell me how I can get all of my music onto all my devices? I have a lot of unpurchased items which I got from CD's.

Thanks in advance for any help.