Hello. I wanted to ask if breast milk could simply disappear? I don't …

Hello. I wanted to ask if breast milk could simply disappear? I don't want to detach the child from the breast but my chest is already empty. The daughter only asks for it at night. During the day she doesn't suckle, maybe this milk has disappeared? At night when she cries I give her the breast immediately, but almost nothing comes out. Can it be increased now?