What WILL help you is building more defensively and farming and looking to make plays in other lanes. Not building damage and continuing to try to 1v1 the fed Riven you gave 4 kills.
not going to be able to farm if I rush a tank item
If you are not a tank building heavy defenses actually sets you behind, because you won't hit your peak when you need to. At some point, non-tanks need to be dealing lots of damage to effectively swing team fight, and if you've built nothing but Sunfire and Visage, you are not going to be contributing anything once late game rolls around.
If you are behind, yes, you do need to modify your build. But that doesn't mean building things that don't actually compliment what your champion does. For instance, if an ADC is behind and can't afford a BFS, they can make do by rushing Youmuu's for the AD and lethality to still give them some sting. They can still build damage and make a comeback, because eventually they can ramp up into a full carry if the game drags on
I made a post about this just the other day. Ticks me off so much when people don't itemize effectively and still feed their ass off.
