Breast engorgement and supply

A • expecting baby #1 March 2015!
FTM here, exclusively breastfeeding my 3.5week old DD and I have been finding between feedings my breasts are no longer engorged at all, she seems less satisfied after feedings too. Is engorgement an indicator of supply? I worry she isnt getting enough and am hoping to avoid pumping until shes 6 weeks so i have no way of checking. Any advice moms? Xo