I've been having a problem with my custom made mods deleting themselves some how. I have no idea why this is happening. After experiencing this twice, I tried to back up my new mods in another folder from the Data files but the .esp files aren't even in the Data folder.

Whats going on? Where are my .esp files?

It sounds like you're running Windows Vista or Windows 7. If so, http://cs.elderscrolls.com/constwiki/index.php/Windows_Vista