Katarina skills stopped working

I was around level 8, ranked match, solo mid playing as katarina about 20 minutes ago.

My Q, E, and R skills stopped working.

W would still work, which was very odd. Also I tried to B, but it would not work.

I wasn't disconnected as I could still auto minions and W them.

I found out the R would not work when I tried to engage on 3 very low health members of the other team.. that was really sad lol.

after they killed me (while i stood there helpless lol) I respawned and experienced about 30 seconds of odd server lag, though i refreshed browser pages and they were working fine.

After that, my skills were working again.

I've experienced a similar problem before on a different computer from this same location, though I can't remember the details. I belive it was with a different character and only one or two skills were not working. The skills worked again after I died.

Thanks.

PS. we won the game anyway, fortunately :)