Tips for dealing with Salt and Stress, and accepting YOUR OWN mistakes?

Alright. I get salty. I get really angry at minor things. Like, REALLY angry. Probably moreso than any other player I've ever seen. The key thing here is instead of taking it out on other people, so thankfully I don't have to worry about being banned, or being toxic.

I take it out on myself. Not gonna go into detail in that regard though. I don't get angry if my bot lane goes 0-12, but if I mess up ONCE, even if it doesn't kill me, I am immediately bearing down on myself, and making myself miserable.

I miss League. I want to enjoy League again. Hell, I want to enjoy gaming again. I suppose this isn't a league exclusive thing. SC2, HotS, Hearthstone, Smash, even many single player games. I make ONE mistake and that's it, any semblance of fun is gone. It's lead to many moments of me just sitting at home in my free time, not wanting to play anything because I know I'll make myself upset.

Now I know it's a bit of a longshot, but I'm wondering, fellow players, if you happen to have any tips, tricks or advice to help me be able to look past my own mistakes and have fun playing games again? I wasn't always like this, I don't know where it came from or what started it. I used to be able to play and have a great time.

I miss having fun playing games.