3 wks PP no more weight loss?

Hoda
So the weight was melting off the first two weeks and now all of a sudden the past week I've lost not even one ounce. I've been really watching what I eat but haven't incorporated any sort of excercise into my routine just yet. I'm exclusively pumping every two-three hours. What can I do to start losing weight again? I'm ready to say bye to this flab!