[GAMEPLAY] Sejuani W ability

I was playing sejuani and around mid to late game, my w just stopped working. I tried standing next to things and only casting that to see if it was an animation bug on my computer, but it did nothing. My ability went on cooldown and it consumed the mana. With it being her best ability for damage, it made me very useless. I don't know what caused this but i would like to know if anyone else has the same issue.