sims 4 keeps crashing

hi please help me! 

every time I go onto the sims I can play it fine but then after about 20 minutes it just freezes and my only option is to force quit. I get mad because I can't save my game. 

I play on MacBook Air 2018 model and have been playing sims 4 on it ever since I got it at the start of 2019.

it also always freezes whenever I shut the lid of my laptop, or keep my game on paused for a few minutes.

I have NO custom content or mods and I have tried repairing game through origin.

this issue started happening the day that sims 4 university came out.

im so annoyed because I love this game but I cant play anymore, please help me

thanks in advanced 🙂