This is the best and most complete site I use for watching this.
I just play with the differnt links to learn what it is and how to understand it. Been paying attention to it for about 2 yrs now.
It always corresponses with how my body is feeling. Agitaited, calm, energized, low energy, and so on. My sleep cycle is a mess during these huge swings..
Anyway I hope this is what you were asking.
Be well.