iPod touch is no longer syncing

I was syncing my iPod touch, as I was doing that I deleted an app that is not on the iPod from iTunes, when I deleted it I deleted it to the recycling bin, then it told me that an itunes temp file (didn't pay much attention to it because I didn't know anything was going to happen) couldn't be deleted and asked if I wanted to try again, I canceled. I checked the recycling bin and the app I deleted wasn't there, I checked the app folder on windows explorer and couldn't find it there either, not that I cared, but I found it weird. I thought everything was fine so I shut down iTunes. I came back later and opened it to find that everything was deleted off of iTunes, I checked the iTunes folder in explorer and found that no files were actually deleted, I'm guessing that the library file got deleted. I backup my entire iTunes library at the beginning of every month and put it on an external hard drive, I deleted the iTunes folder on the computer and copied the last backup. I've done this before when I buy new computers and have never had a problem, but this time, iTunes won't sync files from my iPod. I have three updated files and two new apps on my iPod but iTunes won't add them. iTunes will add files to the iPod but not vice versa. Any help would be great! Thanks!

Steven Powell