Body clock

I overslept today and only woke up for work at 10:00.  The strange thing is, given that I've been getting up for work at 7:00 for about 3 years now, I felt amazing all day, like I was awake at the right time, as opposed to the sort of time slip jet lag I think I usually feel.  I know I spent 10 plus years working in clubs and bars, so obviously getting up later and going to bed later, but it seems like the effect will never go.  It wasn't just the extra sleep.  I can sleep for 12 hours and still not feel that good.  Maybe I should look for a job where I work nights.