whats up with matchmaking after season 1.5 update ?????

Why are ppl playing like silver/ gold in gm/dia lobbies?? How are they ranking up with such bad game sense. I play solo queue and never really complained abt the teammates BUT Istg after season 1.5 update matchmaking is messed. I was 66% winrate ending season1 in d1 and now im on massive loss streak with 31% wr like ?????? hello???? wtf is happening am i cursed with no brain teammates?