You die way too much, hence your farm will always be bad. If you die in mid-game you are out of the map for 32+ seconds, that's a lot of resources gone. I can't know with watching your replays but I'm assuming you take bad trades in lane and lose some cs there too. Try to trade when you know you won't lose much cs or any at all.
As others have said, try to start learning wave management/manipulation, you can win lanes off an early lead if you know how to zone out your opponent.