When starting up my game, everything was gone. My saves, my donwloads, everything.
This problem mostly occurs if you accidentally move your user directory to a different place (with Windows, this can happen very easily). If the game does not find the expected user directory (or any of the folders it needs), it recreates a new folder but that will be empty so that all of your downloads/saves are missing.
A second cause can be a patch. There were incidents where a Origin or game update deleted the user files. Because of this, you need to make a backup of the files before updating Origin or the game. Best is to backup after every extended gameplay.
In case of the options there’s a third possibility. If you update your drivers (especially the graphic ones), all options will be reset to factory settings. This can be very annoying especially since the age settings are also stored in that file.
Search your hard disk for the lost folders. Looking for *.sims3, DCBackup or DCCache is your best bet to find the stuff. If you can locate your lost data this way, simply copy everything in the newly created folders and your stuff is back.
If an update is the reason for your missing folder or the search turns up nothing, only the loading of a backup helps. If you don’t have one, you’ll need to start over. For the future, make sure to always backup all your stuff, especially before installing an update.
To save your option settings and recreate them easily, make a backup of the file options.ini (also in your user directory). Simply copy that back if the one in the folder gets overwritten.