get run off (one's) feet

To be exceptionally busy, especially to an exhausting or exasperating degree; to be made to work very hard and very quickly. We have three parties of 40 scheduled for the dining room this evening, so all of our floor staff are going to get run off their feet. With three young kids, it's hard to remember a time when I didn't constantly get run off my feet.

be/get ˌrun/ˌrushed off your ˈfeet

be very busy: In the last few days before the holidays, the sales assistants were rushed off their feet.