[GAMEPLAY] Fizz E became unusable

Was playing a game of Def Not Dominion as Fizz and towards the end of the game, I was unable to cast my E. The ability apeared greyed out, as if I hadn't put any points into it, but I had it maxed out. I got hit with a Garen Q at some point, so not sure if that's what caused it or not. Anyways, it was unusable for the last 2-3 minutes of the game.