Milk Supply

Unfortunately my days at home with my Little Man are quickly coming to an end. I go back to work on Wednesday. He has been EBF since birth. I've been trying so hard to pump and save but since I feed on demand it's been difficult. I don't have anything against Mom's that give their children formula however I want to avoid that if st all possible. I am drinking the Mothers milk tea and trying to pump at least twice a day but I am only getting around 2-3 ounces each pump and he seems to be eating about 4-6 a session. What can I do to get my supply up? Any help would be greatly appreciated. I really don't want to have to turn to formula when I am so far on this journey already! Thank you!