She is four months complete now. Exclusive breastfeeding is highly recommended.
But if you have very less and baby is not getting enough and baby is crying, you can start other Feeds. Try little warm water at frequent intervals first. Formula mil can also be tried but how our baby respond will depend on each baby.
Colic can also cause irritation. Have you tried Colic aid drops?
Ragi puree and all should be very liquified and given as they are just learning to swallow.
Next Steps
Banana smashed or boiled carrot potato in puree form can be given but should be watery and not too thick. Please feed in upright position.
Health Tips
Some days due to maternal tension, breast feeding will be less
Try relaxing and mother should take good amount of fluids too