Oo normal yan, especially sa first few days! Yung uterus mo bumabalik sa original size niya after birth, at ang breastfeeding actually triggers contractions na nakakatulong sa process na yan, kaya sumasakit talaga ang belly, parang mild cramps. A few of us first-time moms were so worried about the same thing, pero wala lang after a week or two naglessen na. That said, kung ang sakit ay sobrang intense o may unusual bleeding, better check with your OB just to be safe, mas peace of mind lang para sa'yo. Congrats sa baby, mommy!