Is this normal when losing pregnancy weight?

My son just turned 1 in January and I decided it was time to lose the baby weight. I no longer had the excuse of "I just had a baby" so something had to change. About 4 or 5 weeks ago, I started going to the gym 6 days a week, and I do 30 minutes of cardio a day and 30 minutes on machines. I alternate between legs & abs and arms & abs. I have definitely lost inches (I completely forgot to take my starting measurements) and I've gone down a pant size but I have not lost a single pound. Is this normal? I am not sure if having a baby has something to do with it or not.