Oo normal yan, mama! At 21 weeks maraming changes sa digestion mo dahil sa hormones at ang uterus mo ay lumalaki na, kaya sometimes mas mabilis ang metabolism at hindi ka ma-regular sa bowel movements, a few of us pregnant moms nag-experience din nito. Try mo lang mag-drink ng plenty of water, kumain ng fiber-rich foods like oats at fruits, at light movement like walking, at usually nag-settle na after a few weeks. Kung sobrang severe or may blood, then consult your OB na lang to be safe, pero mostly it's just one of those pregnancy things na annoying pero harmless!