So I am about 3weeks postpartum I had a C-section n I've been pumping my breast I don't feed him…

So I am about 3weeks postpartum I had a C-section n I've been pumping my breast I don't feed him directly from my breast b/c I have flat nipples anyway I've gotten so much smaller almost feel like I'm 17 again now I am wrong for wanting to take advantage of the fact the pumping is slimming me down? Like I've been big also all of my life but I think I'm ready to lose the fat and the weight.