breast milk, bottle fed babies

I have a question for the Moms who are bottle feeding their babies with breast milk. How many ounces does your baby drink per day, specifically during the day (~7am to 5pm)? Am starting back at work next month and am sending my 7 week old to day care. I need to figure out how much breast milk to send with her each day to get through the day. I understand every baby is different so am only looking for the intake on average. I also should probably start her on the bottle now, but the thought depresses me so much that I have been procrastinating. Thanks for your help 😊