PLEASE HELP - Casting bar does NOT appear and also major lag

Couple friends and I just started playing on Warmane, been testing out both WOTLK Lordoreon. We decided to give Warmane a try after coming from DalaranWow, so we already had the Wotlk game client installed.

My couple friends and I are having the same problem when playing involving major lag, particularly when casting a spell. When casting, the casting bar doesn't even appear and it really lags to the point where it's unbearable. I have no idea why this is!

Please help as we would like to actually start playing.

Thanks.