Breastfeeding question..

Alissa
My 6 week old son has recently went through a growth spurt and will sometimes give me a 4 1/2-5 hr stretch of sleep. I EBF and don't want my supply to go down. Even when he wakes he'll sometimes only eat for 10 minutes and be satisfied. I've never been one to get engorged or leak..I'm just worried my supply will go down. Any advice?