Minecraft Chat

what has happened is that I came on to my friends server and I was busy working where I wanted to see how it was like to be killed by a enderman and please note I am not on a modded server then I put myself into gm 2 and then all of a sudden once I was killed by chat just popped away like it was not even there but the strange part is I can still type and say things that people can see but I cant receive any msg back from anybody even if they are talking to another person PLEASE I NEED HELP HOW TO FIX THIS!