Pumping question.

My DD is 4 weeks old. I just began building up my stash this morning. I pumped after the first more feeding as I have seen previously suggested and got a total of 2 oz. Is that an okay amount for just beginning pumping or should I be getting more at this point? I am using Ameda Purely Yours and I feel like one side doesn't have as much suction as the other, so I'll be calling customer service later today.