What you can do is create households and lots with all your CC. Export them. So you get Sims3Packs with all your CC in it. I know it takes time especially if you have plenty of CC. But you can easily get it back in your downloads folder this way.
And don't forget to always keep a full backup after... Because you never know.
About backups, do you use Time Machine ? If yes, maybe you have a Time Machine backup of your CC already.