Your body is exhausted, but your brain is still replaying the day and planning tomorrow. Joe's take is that your nervous system never got the signal that the day is over.
His wind-down starts an hour before bed. Lights go low, the phone goes off, and he mixes his Revyval PM (magnesium, glycine, theanine, and apigenin, with no melatonin). Then he shuts it all down and lets the night do the work. The full setup is in the Sleep Reset guide in the Life Library.
What's one thing you could shut off an hour earlier tonight?