Decrease milk supply

Monica

Last couple of days my milk supply in the evenings seems to be going down, I pump every 3-4 hours and I’m lucky to get 2.5-3 oz of milk... I’m pumping and giving her my milk in a bottle but don’t understand why my milk is going down when I haven’t done anything different... she’s eating more so I’m also power pumping once a day as well... I’m At a loss