Trying to establish my supply...

Baby Bouchard

Insurance finally approved a pump for us due to DS originally being labeled failure to thrive due to my supply. He lost over 22% of his body weight in his first week and only gained weight once we supplemented with formula. He is having terrible gas and constipation issues with formula so I'm trying to get a supply established so that we can go back to exclusively using BM hopefully and nix the formula. 

Started oatmeal and mother's milk tea yesterday night and tried to pump today. The pump we were issued is a Medela dual electric advanced, after 10 minutes I got an ounce total.

Any advice, tips, hints to help me with my supply.