stagger under (something)
To move or walk in a swerving, unsteady manner due to a weight or pressure from above. I've got so many books to bring up now that I stagger under the weight of my backpack when I walk home from school. The poor donkey staggered under all the bags of equipment the miners piled on top of it.
stagger under something
to struggle or totter under a serious burden, either a heavy object or a serious problem or responsibility. The welfare budget is staggering under the burden of having to care for many people. Sam staggered under the heavy load and finally fell.