Bug in a group

I was doing a dungeon while the people left and I don't know why, I stayed alone but my character continue with the group but no one is in. I can't leave that group, in my character appear a sword like I was DPS and I can't receive an invitation too. It said I am in group and if I try to invite someone appear that the player isn't in my stay. My character is lock and I can't do dungeons or something related a group or a raid, so I can't do nothing. Is there any solution?

type this on chat:
/script LeaveParty()