my 4 months old baby jerks n moves his head back in my lap while breastfeeding from about a week . He is drinking lesser milk n doesn't want to drink milk. What could be the reason? Earlier he used to demand in every 2 hours. Now he's not drinking much plus he sleeps for 7/10 hours for about 2/3days without asking for feed. He looks hungry but while nursing he keep jerking and doesn't want to take nipple after 2/3 minutes. He is always sucking his thumb. Earlier he was normal