I used to have sleep patterns like that. I found when there wasn’t anything forcing me to be up at any particular time I’d keep about a 26-28 hour day, going to bed and getting up a couple of hours later each day. The rotational shift work I’m doing worked fairly well with that, doing two 12 hour day shifts followed by two 12 hour night shifts, then four days off to reset.

I found that the patterns changed as I got older though - I went through a period where I stopped being able to stay up overnight and changed to doing all day shifts, and have now moved back again to the rotating shifts which are working ok again, but I’m finding it harder to sleep during the day than I used to.

I always found the most important thing is to not stress about when I ‘should’ be sleeping, or how much sleep I should get. I also cycle through periods where I seem to need around 10 hours sleep a night and others where I only seem to need 5 or 6. I try to just let my body do what it wants as much as I can within the constraints of work etc. and not stress about it too much. If I start to think about it too much it just adds another thing to be circling my brain and stop me from getting to sleep.