I wouldn't say I'm in the "all nighter's club", the way I put it is that my sleep cycles independantly of night and day. I'm just as likely to be awake during the night as I am during the day, and just as likely to be asleep during the day as during the night. The position of the sun (or rather, the earth's rotation) has no bearing on when my body is ready to sleep.
The only difference is a do sleep a little better at night, but that's probably because there's less noise disrupting me.
I have tried many, many times over the years to force my body to sleep on a proper schedule, to no avail. I become severely sleep deprived, my cognitive function goes way down, it's completely miserable. A few times a new doctor has insisted I get "disciplined" with my sleep schedule, and I have humored them in order to demonstrate that I genuinely cannot change it. They would watch as I grew worse and worse and they finally admitted that I should just sleep whenever I can. Sometimes I can "nudge" my schedule a bit by staying awake longer or by taking pain meds and muscle relaxants for sleeping a little earlier than I normally would, but I have to be careful to not attempt too much of a change or it doesn't work and then I'm
really messed up.
If not interrupted my body does have a rythem to sleep, it just doesn't happen to coincide with the earth's rotation.
Once, back when I still had a mild case and was somewhat normal-ish, I decided to go a week on a very strict schedule. I had been to a sleep specialist, I implemented all suggestions, I went to bed at 10 pm and lay there in the dark until I fell asleep, and forced myself to get up at 9 am. Every night I lay awake until around 3 or 4 am, and then forced myself to get up 5 or 6 hours later. This happened night after night after night. By the time the weekend came around I was very sleep deprived and finally decided I'd let myself sleep in as long as I needed to.
I slept for 18 hours straight.
This is the story I tell to people who claim that if I just did the right things then my body would conform to a given schedule. It doesn't. It won't. There's no "hump" to get over and then things fall into place...sleep is this amazing thing that doesn't happen automatically, so you learn to take what you can get when you can get it and be thankful you have it at all.
How strange our lives must seem to others...