Have you tried creating a new Sims 4 folder to see if that will help?
Do this by moving or renaming the Sims 4 folder in the Documents folder [C:\Users\Username\Documents\Electronic Arts\The Sims 4]
The game will create a new Sims 4 folder next time you launch/play the game.
Try checking the gallery/library to see what you find before adding in any of your mods and saved games.
If it's working, start copying over the files and folders described in the link below:
Files and Folders To Add Back In
http://www.carls-sims-4-guide.com/forum/index.php?topic=29292.msg401669#post_FF2AB-- When you move or rename the Sims 4 folder, the game will no longer be able to find it. When you go to play the game it will create a new folder.