what even happened bro

i have a MacBook air from roughly two-three years ago, and i have downloaded the sims 4 game on it.

i notice that the laptops fans go off pretty intensely when im playing

but the thing is, recently i was playing and i left it on for about half an hour without making a single move and my screen went completely black and i could only see the mouse and move it around, the fans are still going off btw.

i tried opening and closing my macbook, and everytime i do, the screen is still black, i can still move the mouse, the fans still go off but theres nothing else i can see? how can i check if sims is still running? how can i bring back my screen?