u/AvocadoTempuraRoll

Hello guys, might sound stupid but I want to know what exactly is a "letdown"??

I am 7 weeks PP and im pumping + breastfeeding. My breasts only feel hard and engorged if i go 5-6 hours without feeding my baby. I never leak from breast while i feed from another breast.

How do i know if i have a letdown?

Is it mandatory for everyone to have it?

Is it something that develops over time?

Baby is gaining well.