Mouse Input Lag (since small patch)

Hello, I've been having a problem rendering the game unplayable since approximately two days ago. Two days ago my client downloaded a very small (3-4 MB) patch. Afterwards and since then I will have many periods in-game where my mouse "loses control" for anywhere from 2-5 seconds. This costs me plays, kills, etc. It is game-breaking, for me at least. I don't usually post on the Forums but I'm at a loss of how to fix this.

Thanks for any input.