Fizz Bug 5.15

I was in a ranked game and for some reason in the middle of the game i couldn't use my e. it didn't effect very much and it went away for after a little while but its just weird because it wasn't on CD but i still couldn't use it. could it be because of the items i built or is it just my own computer acting up? please give me some incite the link above is to a image upload site and that's where i posted the image for anyone to see