The expression busyness (line 19) is in italics to

confuse the reader by referring to all of Peter Bregman’s financial problems.

show that the author is not immediately accessible to talk to other people at work.

point out that all the author’s enterprises are giving him a succession of bad results.

highlight that the author is referring to himself as being extremely full of activities.

convey to the reader that Peter Bregman has dedicated himself to the company that he owns.