Stop picking Yasuo top expecting to be a fighter

If you build and play him no different from how you would against a squishy mid or bot lane opponent, he doesn't magically get Tryndamere's ultimate and passive to be able to continue a sustained fight when the enemy's dealt kill damage to him. If all you have is a Phantom Dancer, you are still most likely going to lose against the beefier top laners.

You need to keep in mind that you have low base stats even compared to other assassins. You're not to be able to take on a half decent Garen or the like just with your anime-protagonist belief.