[Mac] - I can't click on anything in the game

I play the Sims 4 on Mac, downloaded it ages ago and haven't had any problems at all with the base game or any expansions up until the last couple of days.

The game lets me play as normal for a varying amount of time and then suddenly crashes and won't let me click on anything on the screen. When I hover over buttons the annotations are still appearing and all the keyboard shortcuts still work. I have tried to quit the game but can't because I haven't saved my progress and I can't choose to save or not save the game (since there is no keyboard shortcut that I am aware of.)

I then try to restart/shutdown my Mac but I can't do this either because 'The Sims 4 cancelled Shutdown' because I haven't saved the game. So I cannot close/restart the game at all, and am just stuck with it open, not doing anything.

I was wondering of anyone else has had this problem, if anyone knows what I can do to get out of it and how to stop it happening again?