Just because you are not ahead does not mean you have lost
Did you lose your lane? Did you get counterjungled to the point where you have a Support's income? Did you get ACE'd at Dragon? Did you face Teemo Satan in lane?
Well, that means you are behind. And when you are behind, you are still in the game, and that means you still have a chance at winning. Your wins should not consist of all stomps; you have been matched with opponents of similar skill levels as you are. It only makes sense for you to have close games or games where you will struggle. That's part of climbing the ladder. The ladder is supposed to challenge you, not give you an easy path to Diamond or Masters.
Basically, if you are behind, you can recover. You can still punish the opponent for silly mistakes such as a 20 minute Baron or a poorly executed turret dive. Even little picks, such as getting that Vayne in your Jungle can turn the tables around. Just do not give up.
carried hard