Weight gain immediately after birth

I just delivered my baby 2 days ago. I'm now at the confinement centre and to my horror when I stepped on the weighing scale, I did not lose any weight but instead put on 5kg! I had been constipated since a few days before birth but given that the baby weight + waterbag + placenta, shouldn't I have lost some weight? Had been trying to get breastmilk too but it's still in drops. I did not overeat in hospital too. But I am visibly very puffy. Anyone can advise me? This is depressing. #advicepls #firsttimemom #pleasehelp #FTM #firstbaby