When the alarm goes off and the first thing you do is calculate how many hours until you can go back to sleep you know there might be a problem!
I've had clinical days where I've had as little as 2 hours of sleep. Not something I'd recommend. Ever.
Most nights I average 5 to 6hrs of sleep. I try to have a mini hibernation session once a week where I'll sleep 10 to 12 hours, although sleeping that long tends to make me feel groggy.
It is possible to sleep more- but you can't have your cake and eat it too. It's about choices- Right now I'm choosing AN and SNL over sleep!!