If on windows, look in your Documents/Electronic Arts/Sims 4/Tray folder and see if it's full of files. If it is empty, then somehow it got wiped. (I have no idea how that would happen from an update.) The only way to recover it then would be if you had uploaded everything to the online gallery or had save games with those items still in them. You would then have to re-download / upload all your stuff.
If the Tray folder is still full, then everything is there and you haven't lost anything. It's just not being associated with your account for some reason. For that, I'd try signing out of the EA app, restarting your pc and then signing back into the EA app. Sometimes the EA app won't pick up all my games or just act weird. Usually simply restarting my pc works but sometimes I need to sign out / sign in or restart the app a few times. It's fiddly.