I'm sorry to hear you are having issues with iTunes. The article below will suggest that you uninstall and reinstall the iTunes application.
If this issue is with content in your iTunes library, if you have a Time Machine backup, you could restore the library from an earlier date.
Click on the link below to see more details and screenshots.
I've quoted some helpful highlights for you:
With Time Machine you can go "back in time" to restore files, versions of files, or your entire system.
You can use the timeline on the right side of the window to reach a certain point back in time (the timeline shows the times of all backups on your backup drive). If you don’t know exactly when you deleted or changed a file, you can use the back arrow to let Time Machine automatically travel through time to show you when that folder last changed.
Note: Dates in pink indicate the data resides on your Time Machine backup device. Dates in white indicate the data resides on your Mac. In OS X Mountain Lion and Lion, portable Macs have the feature of local snapshots. See this article for details.
To restore, select the file/folder and click the "Restore" button. The file will automatically be copied to the desktop or appropriate folder. If the file you are restoring has another file in the same location with the same name, you will be prompted to choose which file to keep or keep both.
I hope this information helps ....
Have a great day!