midgame lag-like glitch

RiCexEaTeR

Randomly (as in I have found no cause or trend) my screen would bob up and down as if i were stuck or lagged out. I could still shoot/bite/etc but not move. Then it starts getting weird (see photo) My internet connection was fine and I could still use the computer (duel screen), sever was still up.

Weirdest part is that when I use commands disconnect///retry I get an authentication error but when I join server from the menu it works just fine.

Help?

[HEI] Spade

Don't know :S for the authentification error, restarting steam fixes it and for the disconnect command, if it's not working, use "exit" and it will close the game.