Difficulty breast feeding.

I need help!!!!! My baby girl turned two weeks & 3days today, i was making 4oz total but now i am barley making 2oz total. I am only pumping due to her not latching on & not latching on with a nipple shield. I still wanted her to have breast milk so i pump. Normally pump every 2-3hrs. Any ideas to help boost milk supply? Or anything you have tried that worked? I am eating healthy and drinking 8 glasses of water a day, sometimes more. Please help!!