How could I have won

Update: this was for sure a tilt rant looking back but thank you to everyone who took the time to respond. I appreciate all the feedback

B4 NA

Laning against a veigar, it's 0/0 the whole lane, no ganks either side. I'm up 50 cs. Jungler decides to try stealing grubs, gives veigar a kill. From there, I'm still hard winning lane but he keeps roaming and picking up easy kills. Was focusing on farming the wrong decision? My KDA ends up looking horrible because the fights are super chaotic and i keep getting cc'd to death, but I didn't die until more than 20 minutes in, and my opponent was already fed at that point and the game was practically over

Game id: 5236579411