Graphics Problem - I Can't See Players/Environment

[Valewind]

I was playing earlier today with no issues. Logged back in this afternoon and on the character select screen I can't see my players' character models or the environment. I can only see my players' names and the character select menu. Same goes for when I log in. I can see the sky but can not see any players or walls or the ground. I can only see players' names and the chat window and the other windows like the actions window. Anyone know how I can fix this? Thanks.