BreastFeeding--> How do I maintain my supply

Tricia
Ok ...I got the hang of the breast feeding thing.. I go back to work pretty much next month.. Now I need tips on how can I maintain my supply and stack up on frozen breast milk. I drink 66 oz twice a day but I don't see my supply boosting.. I kinda. Seen it decrease and I just wanna know. Why ??? I try to pump and I only can make 1oz of milk on each breast.. Thats kinda weird.. My fiancé has been giving Tari the frozen breast milk that she need when I go back to work.. Now I'm down to 4 bottles. Ugh.. Not only that I have to go to bathroom all the time... Help!!!!! What should I do!!!!