You can probably recover your playlist. (Instructions for Chrome)
On the computer you used grooveshark on: visit the website, open developer tools, open "resources tab", click on local storage->grooveshark.com. Now find the key called 'libraryXXXXXX' where the X's are numbers. Right-click it, "edit value" and copy/paste that data here: https://json-csv.com.
Source of instructions:
http://www.reddit.com/r/Music/comments/34goss/meta_groovesha...