How many oz should I be pumping?

Ashley • Navy wife, Mom of 3, Zumba Instructor, Animal Lover
My son is 8 weeks old and has been exclusively breastfed. He always seems to be gassy and fussy and I'm not sure if it has to do with too hard of a letdown or not enough milk, or both (I've already cut out dairy). I just started pumping and have been getting about 3 oz total when I do. Is 3 oz enough to sustain an 8 week old per feeding?