Usually, temporary "indigestion" in infants can be due to a viral attack on the stomach. Teething
can also produce a day or two of fever
, loose stools, irritability and crying with tummyache. The more worrisome problem could be gastroenteritis
, in which case, the child must be seen by a doctor. I suggest that you continue to give breastfeeds, normal weaning diet and also oral rehydration salts solution (ORS) till (s)he recovers. This may take a few days to about 3-4 days at the most.