How to pump 100oz in less than a week

Please help I unexpectedly have to leave my baby next weekend to go out of town she will be staying with my mom. I ebf and just pump here and there just because so I only have about 25oz in my freezer. I’m thinking I’ll need to leave her with close to 100oz to be safe. Question is how? If I ebf and don’t have much of a pumping schedule. When I do pump I get maybe 4 oz from each side. I am freaking out I don’t want to give formula because I don’t know how her little tummy will react to it. Any tips and tricks