I have a weird problem that when I'm around people I fall asleep before midnight, when I'm alone for several days I start staying up way too late (1:00am and be

I have a weird problem that when I'm around people I fall asleep before midnight, when I'm alone for several days I start staying up way too late (1:00am and beyond). Normally after work (which can be anytime between 4:30pm and 6:00pm) I have to start winding down and stop thinking about all the work I did and have to do. I either read for 1-2 hours right after work or exercise such as yoga, running or soccer. That calms me down mentally and I go home, cook dinner, watch one tv show or play on my 360, shower and then iron my clothes for the next day. Showering and ironing clothes send a clear signal that it's time to go to bed.