Kate Middleton is taking a step back from public duties after having a planned abdominal surgery, but fans of the Princess of Wales quickly began to speculate on social media about her whereabouts after Prince William failed to make an appearance at King Constantine of Greece’s Thanksgiving Service. “Kensington Palace made it clear in January the timelines of the princess’ recovery and we’d only be providing significant updates,” her rep for the Princess of Wales told an outlet. “That guidance stands.” “Where is Kate?” was trending on Twitter after a rep shared that the Prince of Wales was una…