What do you do when..

You're playing ADC and your other lanes feed some kills to melee adcs with huge steroids such as Yasuo, Xin Zhao or Fiora. I personally think champions like these are overpowered but I'm probably wrong so instead I'm asking for advice on what to do when those types of champions get ahead (which they always seem to). I work on positioning as far away from them as possible in fights, but their gap closers allow them into the back lines with ease. I tried building two armor items just to survive in one match, but then I don't have the damage to kill them. It's so frustrating when you're doing alright in bot lane then some 3/0 Fiora comes down, presses R and you die, because as an ADC you don't build armor in lane and it's just so easy for them to roam, get kills and snowball.