I'm sorry, James. But I'm very busy with my work. (up) -> I'm sorry, James. But I'm ………………………………………….………………………… in work.

I'm sorry, James. But I'm very busy with my work. (up)

@ I'm sorry, James. But I'm up to my ears in work.
up to your neck in work - up to ears in work - to have too much in your plate