I used to think that about myself. Now I'm pretty sure it's just the result of having light pollution (lights outside candle temperature and brighter than three

I used to think that about myself. Now I'm pretty sure it's just the result of having light pollution (lights outside candle temperature and brighter than three or four candles) including glowing screens, electronic device hyperstimulation, and the Internet info treadmill, after 9:00 or so. If I give myself a good long stretch of low light and no electronic toys my "28-hour clock" not-so-mysteriously turns into an ordinary 24-hour one. Being outdoors and active as much as possible during daylight hours also helps (especially in Summer, when dark hours are in short supply).