The game is not rewarding towards good players.
Going to legend is a pure grind. Try to notice why you lose when you lose, if there are cards that are constantly not useful and can they be replaced. After that, tune your deck and stop making same mistakes. Grind. You are legend. Easy.
Most of this is true. Not sure why you wrote not rewarding to good players...
I think what you meant is RNG allows bad players to win more. A good player will already be doing the things you mentioned and won't have the aforementioned LS.
That said OP. Tilt will wreck you, mental walls will wreck you, RNG can wreck you. If you're experiencing any of these things, take a break, go outside come back when you're refreshed.