Gaming Notebooks

My day was ruined when I sat down after a long day, I was just gonna play some Sims 4. A game that isn't demanding at all that my laptop runs on max settings and has been since i bought it. But now it lags so much that it's barely playable. I just played it this morning before heading out for brunch and it worked fine. Now when i come home I can't play it. I tried my other game Hell Let Loose and I didn't start a match because I noticed the main menu worked poorly, delayed mouse, stuttering, overall laggy.

I'm new to computers, this is my first one that I own myself. So I don't understand much of performance numbers and RAM and what all that means. But I know that it's all been running smoothly before today, and that the games I own were what this laptop could handle. 

Is my computer broken? I've tried updating graphic card drivers but they were at the latest update(as expected).

I don't understand what to do, I feel lost and honestly very anxious that my brand new expensive computer just started acting like this so soon after I bought it.