Where did my content go?

Did you simply try to restart your PC and open the EA App again? I have to restart occasionally because my Sims 3 gets lost.

Did you try to repair the game?

I had something similar happen a while back. A couple EPs were missing in the EA app. Next time I tried they were back, so I assume it might be a temporary thing in your case, too.

Logging out/in might clear some stuff.

That's just the EA app being the app. it sometimes randomly forgets stuff. restarting it a few times can sometimes fix it. although it doesn't matter what the app thinks as the files are still installed

Try a restart on your computer. Clean the cache from the app. If all else fails, either repair your game or download the EA App again. Best of luck.