It's always good to point the finger at yourself and ask what can you do to improve. You have the right attitude. Sometimes tho man its not you, it's the other people on your team. You could be the best, but if you're surrounded by shit team mates then no matter what you do you cant win.

The one thing I notice in this game is that if you want to truly carry your team then you almost HAVE to pick an offensive character and just keep the other team so busy and stay killin them that they can never recover.

It's a game where you have to rely on 5 other people, and if a few of them are having an off day its going to reflect on you as well. Then the more you play after that the more you tilt because you feel as thought you have to make some insane play to save the game. That's when the mistakes come in. Just take a few days off from competitive and come back to it.