Help!!

I have 10 day old twin boys, I have had trouble with latching so I am now just pumping and bottle feeding. The first few days were great getting plenty of milk to feed both babies. Now I feel as though my supply has dropped. I am struggling to get enough milk to feed both babies at each feeding. I have tried pumping every 2 hours but I'm only very about 3 oz each time. Each baby is eating 3 oz at each feeding. I have had to supplement with formula just to get through the day. I want to know if there was anything I could do or try to get my supply back up where it needs to be. Any input is appreciated!!