Do you still have your original saved games and CC/Mods? Please do note that some Mods and CC no longer work correctly when the game is updated due to changes in the game code itself.
That being said, here's the easiest thing to try first. Locate your Sims 4 folder that houses your Saved games. (Documents > Electronic Arts >Sims 4). Move that entire folder to your desktop and start up the game. Do not add back the CC or mods yet. Make sure that the game starts up fine and start a new game. Play for about an hour or so allow the game to regenerate the data for the Sims 4 folder and to insure that your Vanilla game is working correctly. Save that game (to make sure the game saves correctly) and then install just a few pieces of CC at a time. This will help you narrow down what is causing your game to not launch properly. Once you have reinstalled your CC and mods and know that the game is working fine, you can add back your saved game by simply switching out the Saves folder.
