In Year 12 I was addicted to gaming. All it did was make me frustrated and angry, both inside games and outside. My addiction was also reflected in my results, as I underachieved massively.
I completely cut gaming out of my life (well, aside from a couple of hours a week on League) in Y13, and spent the time I'd be gaming on more productive things (like sports, revision etc.) and it made me a happier person. I also did well that year.
I'd say cut it to extremely small periods. You'll feel happier when gaming and you can spend the time gained on more productive things.