Pumping help!!!!

Sedaya • My name is Sedaya and I'm 23. My husband and I have been together since 2009 and got married April 2015. We have a four year old daughter and had our second daughter 4-16-16 :)
OK so I'm going back to work next month and I started pumping this last week. It's definitely not enough! I've only been pumping 1 to 2 oz at a time. I'm definitely not producing enough. Any suggestions. I've been drinking lots of water and pumping three times a day. If I can't pump enough I'll have to supplement once I go back to work.