Paul's Illness on the American Tour, 1966

In my previous post of November 26th., I talked about John's sarcastic comment about (obviously) The Beatles being pushed to perform when they were ill.  I found a reference that confirms this.  In the introduction for Read The Beatles:  Classic and New Writings on The Beatles, Their Legacy and Why They Still Matter (Penguin Books, 2006), author June Skinner Sawyers is discussing The Beatles' 1966 American tour:
     "The climate at the concerts had changed, too.  Bomb threats, clashes between fans and police, and even death threats signaled an ominous turn.  It got so bad that Paul McCartney began vomiting before going on stage when the fear became overwhelming."

I haven't seen a reference before this that talked about health problems Paul had in 1966.  He claimed to be "dead fit" in a New Musical Express interview in June, 1966.  But  it's very possible that it was more than nerves that contributed to Paul vomiting and may have been one of the reasons he was stepping out--or was shoved out--of the group in 1966.