By the time he was four months old, he was refusing to take my milk from a bottle during the morning and waiting for me to pick him up at lunchtime to eat. Then I went back to work full time. I would still come to see him at lunchtime. He started out taking a bottle during the afternoon, but by the time he was six months old, he was again waiting for me to come pick him up before he would eat. Also by then he was starting to eat some solid food, which would tide him over until I arrived.
Babies are smart.
They prefer the real thing to even bottled breast milk. If she's truly hungry, she'll probably eat. It sounds as if she knows that you'll be there soon and prefers to wait. You'll probably see that she'll increase her nursing during the evenings, nights and weekends to make up. That's what my baby did.