Boy, am I tired

Tonight, I am working a 12 hour night shift at work, covering for one of the guys who wanted to attend the staff Xmas 'do'... It's currently just a little short of 5AM, and it's still almost 3 hours till home time! I have been awake for about 22 hours now, and am really starting to flag. Mind you , the overtime will be usefull, just after Christmas...