sleep is difficult to count

Last night, I went to bed at 23:30 and again I woke up at 5:00 but stayed in bed and slept more. I think I got out of bed after 9:00 but I was awake for a long time and just thinking. It's hard to quantify exactly how much sleep I got. It took me a little while to fall asleep in the first place. Probably, no more than 8 hours of sleep in total.