If your baby is squirming and crying, it is important to consider changing their formula. Sometimes babies experience digestive discomfort as they are still learning how to properly digest between 4 and 6 weeks. However, if your baby is eating well, gaining weight, and having regular wet and soiled diapers, there may not be a cause for concern. One suggestion is to pause feeding sessions 2 to 3 times (or more if needed) to burp your baby. Additionally, if you have recently changed the nipple size on the bottle, it may be helpful to reassess that change as well. Hopefully, these tips will help ease your baby's discomfort. Feel free to reach out if you have any further questions.