Don't give Cerelac only. Give mashed fruits, boiled and mashed vegetables, mashed homemade food like daal rice etc. add ghee to increase calorie intake. No need of formula

Exclusive breastfeeding is given for up to 6 months. After then, along with your milk, you can give solid diet or complimentary feet. Just don’t focus on Milk because at this age child is required protein, carbohydrates, vitamins, and other nutritious minerals. So if the child is passing urine adequately and passing stool adequately and gaining weight, child is active and alert, then do not give formula feed.

Consult with Pediatrician physically for further evaluation and treatment

Try to increase food quantity Proper food not cerelac