Is transition something that you want? You don't have to switch to cows milk. You can start pumping if you don't already have a stash and then offer the breastmilk via cup. You can also try switching to something easier on the stomach than cows milk such as coconut milk or almond milk. There are so many options. They even make enfagrow which is a stage 2 and 3 formula for infants to toddlers ages 1 to 3 years old. It has dha and other important nutrients