How do people remain positive about this game when you just keep losing over and over? I really do try, but I'm always losing. Either getting steamrolled by Master Yi or Wukong or Zed. This game is really starting to make me depressed. A bit melodramatic to say but I'm just really struggling
Play some ARAM. And I don't mean this in a way that implies you should take ARAM lightly- ARAM mains won't take kindly to that- I simply mean that the games are shorter, skill is less important, and the people are usually a little nicer. Of course if you don't want to lose your summoner's rift skills, and if you're talking about losing in ranked, you could always just take a few normal games where you take the game less seriously than usual. For example, try a new champion, or perhaps an old favourite in a new role and have fun with it. Just try and remember why you play this GAME in the first place. For fun!
I went 1-20 in ranked my first season, meaning this season, of ranked. I hated it. So what I did was I stayed away from ranked for a few months then went back to it after a bit. If you're talking about normals, don't get too hung up about it. Play with friends. If you want to win, try to counter the enemy. Build armour against AD champs. If it's really bothering you, take a break from league for a bit. GL, friend.
I believe it was George Carlin who said this...
"If you're a rich f-ck and you're depressed, just remember that somewhere there's a poor family who would quite literally kill to have what you have. If you're poor and depressed, just remember that there's someone in a third world country who cannot control how bad their life is. If you're in a third world country and depressed, just remember that there's some rich a--hole who thinks his life is terrible compared to yours"
In all seriousness, it's all about perspective. Chances are there's hundreds of people out there in a way worse position who would KILL to have what you have. Just hang in there. 
Send nice people a friend request; less chance of having to go into a game alone.
Go into a Bots game. Almost never toxicity, almost no chance of losing, and you have the opportunity to show some newbies the ropes, or find a new friend. At some point during that game, you should forget that you're mad. May reset your rage settings.
Look at pictures of 'side boob'
Go to the MISCELLANEOUS tab on the left, and read people cry about chat bans when you can see exactly why it happened in the body of their post.
Silly youtube videos: https://www.youtube.com/watch?v=XzxjGEPTPZw
