Low supply

Serenity • 25 married to a wonderful hard headed man have two handsome sons a beautiful angel baby and a miracle rainbow
Im a first time mom and hubby decided we shpuld breast feed and at first i was pumping 300 to 600 ml in a day but now i cant even get 200ml in a day.... i was told that it happens to some women but I've been keeping the same diet i have been the onky difference is i was doing alot of kangaroo care cause i was in the hospital with my son and now he's still in the nicu and i am home and cannot be there everyday. Question is what can i do to get my supply back to what it was... i pump every 2-3 hours and i pump till they are empty. I tried lactation cookies and those didn't work... help please.