Pump Response

Ladies, I need help. I never had to seriously pump but when I did I would get a decent response 3-4 ounces combined. I started building a small stash just in case. I got thrown into a new temp job and now that I need to pump I'm no longer responding to my pump. I cant even get .5 ounce combined. I can only pump once a day at work if I'm lucky so I'm pumping all the time when I'm home and nothing. I'm drinking close to 80 ounces of water a day and eating to my hearts content. How can I increase my output so I dont have to switch my 10 month old to formula while I'm at work?