The mentality that helped me to deal with this is just stop caring about your rank, and just start focusing on yourself in game. If people comm and play with you its a huge bonus, but don't expect it until you're at least ascendant for example, if your team loses 2 players instantly, and its now a 3v5, instead of thinking 'my teamates are making me lose rr and theres nothing I can do, so I'm not gonna try this round/game', think 'ok its a 3v5, we probably aren't gonna win this round, but let me try and play tactically to see if I can make it close'.
tl;dr
life gives you lemons