My baby isn’t eating

S

How do you guys know when your baby is hungry. We used to feed her when she woke up from a nap but now when she does that she only eats an ounce or two. Even if it’s been three hours. She doesn’t fuss in between feedings so I never know when. She sucks on her hands a lot so I try then but she refuses. I’m at a loss- I don’t know what to do. It’s causing her to wake up through the night to eat because she isn’t eating during the day.

She’s not even getting to 24 ounces during the day- yesterday it was about 23 and that was with a middle of the night feed. I don’t know how to help her.