Someone Using My Nickname?

Just a quick question, I logged out from the server and tried reconnecting back because I wanted to change the world server, but then I got a message that was something like:
"Someone is online on the server using your nickname, we kicked him so you may try to connect again"
That scared me quite a bit. I made a small search and didn't find it any similar topics. Is it normal to see that message? Can I know if was there really someone logged in using my account? If there was someone, do they have access to my characters and all?

 

Sometimes the server might just think you're still online for a few seconds and if you try to log back in right after logging out this would happen... Happened to me a few times, No worries, This is completely normal, Especially if you have bad internet like me, Also regarding the title, No one else could have the same username as you, Minecraft doesn't work like that, By the way please post this kind of stuff in the Questions section.

 

what he said

 

as lord bottom chops said

 

Thanks all for clarifying, and sorry for screwing the section thing up.

 

I like the name muttoncocks

 

what about lord bottom chocks?