Worried About Queen's Health

F1 superstar Lewis Hamilton is hoping for the best amid growing concerns about Queen Elizabeth's health ... saying he's praying for and thinking about the Royal Family during the troubling time.

The British driver -- who's currently preparing for the Italian Grand Prix this weekend -- took a moment to share kind words for Her Majesty on Thursday ... saying, "I think she's been such a strong leader for such a long, long time and so resilient."

"I know she's always been a real fighter, so my thoughts are with her. Obviously, I don't have any other more information so I don't know more about the situation."

Lewis -- who received his Member of the Order of the British Empire from the Queen in 2009…