to be too much for sb to manage or deal with; to manage to control or deal with sth
get on top of sb
to be too much for sb to manage or deal with
All this extra work is getting on top of him.
get on top of sth
to manage to control or deal with sth
How will I ever get on top of all this work?
Definiciones del Oxford Advanced Learner's Dictionary, 9.ª edición