Wa'alaikum assalam! Alah, ini normal je for BF babies sebab susu ibu fully absorbed, tapi seminggu tu memang agak lama sikit, better check with your pediatrician to make sure baby okay, sebab sometimes ada other signs yang perlu diperhatikan. A few of my mum friends' babies macam tu jugak, and most of them mula introduce slow-slow makanan bila dah ready (kalau dah 4-6 months) or baby boleh gerak more, yang jumpstart digestion sikit, but ask your doctor dulu la apa best for your little one.