I have been using the Avent Isis manual pump at work and I wanted to spend less time pumping so I could get back to work faster. So I bought the new electric Isis IQ but it seems like it isn't working for me. I can't get a let down and I took 10 minutes on one side and just got an ounce out. Am I not using it correctly? Can someone give me some advice or does it not work at all???