if u dropped down to 1400 yo, i think its not soley your teammates fault, some of it contribute to you.
ive been playing with my 1400 friend from 1400 to 1600 at 5mmr per game, with a win% of 69%
we always get bads like usual, but if you are decent enough, you can still likely carry the game
so i'd just say, play more, start with ez heros like witch slayers, pr, andro, they can really turn the game around if played properly, ganking around like mofos