Help!!

Allie • Hi, im 12yrs old and im in 7th grade.
K so I got my period on Sunday and mine usually last 7 days and are normally heavy. So when I go check to see if my pad needs to be changed it looks like a light flow. In the morning when I change there is hardly anything there but I know I'm on it from when I wipe (tmi) but can someone tell me why this is?