I've been caught out a bit, I spent about 15 odd years not getting to bed until after I'd settled my mother and made sure she had her meds and was dozing off. Which meant, I wasn't in bed till about 0230-0300. Then I'd be up around 0930-1030ish to get her the morning meds and start the day.
Now I'm working in an office environment, I'm having to get up at 0630, but find it's pretty much impossible for me to fall asleep before midnight. So for the last 6 months, I've been averaging around 4-6 hours sleep a night.