ok sometimes what happens is if you updated your game recently but not the mods then the mods can be out of date as in not the same patch level as your game and on occasion mods can get broken by updates/patches and some mod/CC may just be incompatible with another
easiest thing to do is just move your mods folder to the desktop will do and clear the cache files
to delete the cache files go to electronic arts/the sims 3/
•CasPartCache.package
•compositorCache.package
•scriptCache.package
•simCompositorCache.package
•socialCache.package.package
it's safe to delete these files as a new ones will regenerate
then launch your game and see if your sims function as they should if they do then use the save as new save name
DO NOT put your mods back yet,make your mods folder replace your mod resource.cfg file (and no sparkles no intro if you have those ) <----if you have those just launch and play see if all is well then good save and quit
then search wherever you got your mods from and see if you need to get any that are the same patch level as your game and the painstaking part place one mod launch play if all is well save and quit rinse repeat until you run into one that cause an issue remove from your mods folder rinse repeat
tip: anytime you delete a mod OR add a mod clear the cache files as above