iTunes changes video/album info when I play video/songs

I have purchased movies, tv shows, and music on iTunes, and sometimes when I go to play a song or video I've downloaded iTunes changes the name/album/other info on the video/song, and it then changes where it is located in my iTunes folders, and album art changes as well. What is going on?! I've had it happen multiple times to both songs and videos. And unfortunately, even though it renames the files on my computer and in iTunes causing me to not be able to find them, I can not download them from the cloud because the cloud recognizes that those files are ON my computer (even though they're renamed and I would have to listen to thousands of songs just to find what it's been renamed to).

How can I stop this from happening and losing so much media that I've purchased on this computer?! I'm tempted to delete EVERYTHING, and redownload it from the cloud. However, what's to say it wouldn't happen all over again once I've done that?

Please let me know if you've experienced something similar and what can be done to correct the problem.

Thank you so much.