Hello, Welcome to HCM, The symptoms of high fever and passing loose stools are suggestive that your child is having some infection which is leading to all these symptoms. As your doctor as advised ORS solution continue this until the passing of loose stool stops, it also help to reduce the dehydration following diarrhea, continue to give breast milk as your child is willing to consume that. In addition to this you have to check for other signs of dehydration, as the baby is becoming dull and irritated, it should be taken care properly it is not a good sign. I would suggest you to take your child to paediatrician to check for any signs of severe dehydration. Thank you.