Huge skill disparity between my team and enemy team leads to loss streak?

I've lost 8 games in a row now and almost all of them are absolute stomps with no chance of winning after 15 mins. 3 of those games actually started good until 1 player gets caught basically ending the game with inhibs and baron. Even if I get the likes of Gnar, J4, thresh they are completely ineffective vs the enemy as opposed to when any of those are picked by the enemy they destroy us. Is the matchmaking screwed up since the new season? I went from Plat V straight to Plat III because my MMR was good now the game is just taking a huge dump on me.

Losing this much is not fun, what could contribute to putting me with players that have such a low chance of winning vs the enemy?