how much should i be pumping?

Madi • 15, teen momma❤️ Kaysen Grant 5/22/16💙👪
im 3 weeks pp and whenever i pump i only get 2-3 oz from each boob, so i end up just putting them together. thats one bottle per pumping session. i used to be able to get 5 oz each boob each session. i didnt change anything! why is my supply disappearing? 😞