Prince William was “literally sick with worry” leading up to Prince Harry and Meghan Markle’s explosive March 2021 sitdown with Oprah Winfrey. In the latest Kate Middleton biography, “Kate! The Courage, Grace and Power of the Woman Who Will Be Queen,” author Christopher Andersen claimed the Princess of Wales “could hear her husband retching in the bathroom” for a full week before the interview aired. William, 43, was allegedly “too distracted to think of food” over what his brother and sister-in-law would divulge to viewers. Prince William, seen here in February, reportedly made himself “sick with worry” in the days preceding his brother Prince Harry’s 2021 sitdown with Oprah Winfrey. Getty Images William, pictured in 2018, couldn’t keep food down and retched for a week, according to Christopher Andersen’s Kate Middleton biography. AP Page Six has reached out to William’s rep, who did not have a comment.…