If your baby is having an allergic reaction and you're not sure of the source of the allergy, it's recommended to reintroduce one allergen at a time after waiting a week. Keep some Benadryl on hand in case a reaction occurs and stop using the product immediately if a reaction happens. It's also suggested to pump breast milk for bottle feeding and maybe try introducing only oatmeal cereal to see if there is any reaction. Additionally, seeking advice from an lactation consultant or a breastfeeding helpline could provide more guidance on managing allergies and adjusting your diet as needed. Make sure you're using an effective breast pump and the correct breast shield size to optimize milk expression. Massaging the breasts before pumping and applying warmth can also help with milk letdown.