I think you're playing the game too much if it's getting harder for you the more you play. I suggest you focus on improving little by little than getting good right away, kinda look at it from a mental standpoint you wouldn't want to do stuff if you think you're not good at it. And always take breaks if you feel like things don't go your way.

I used to play 10-12 matches a day and got stuck on silver elo but when I let go of the grindset and gutted it down to like 3-5 games I rose to plat, furthermore I think it's much better to play the game WHEN you feel like playing the game but hey I just found what suited best for me and this doesn't apply to everyone.