Changing formula?

Melissa

How do you know when to change baby formula? I been giving my baby Enfamil Neuropro for the past 5 weeks and lately I feel shes been eating less like after she wakes up from her 5-6 hrs sleep, me thinking she’ll be hungry, she only drinks 2oz max and at night she be squirming so much when i lay her down since she sleeps on her stomach, shes 15 weeks, has no trouble sleeping, dirty diapers etc...