Baby isn't interested in eating

Ka

He is refusing the bottle lately. Sometimes he'll go 4 or 5 hours without eating and then when he does eat it's only 2-3 ounces. Anyone else have this issue? Worried it will affect his sleep ☹ he normally does 4 ounces every 2-3 hours. He did the same thing with nursing a few months ago so I pumped and bottle fed and now he's doing the same thing with his bottles. So frustrating!