https://www.bbc.co.uk/news/uk-62836057

"Following further evaluation this morning, the Queen's doctors are concerned for Her Majesty's health and have recommended she remain under medical supervision," a statement said.
"The Queen remains comfortable and at Balmoral."
Prince Charles is now with her and the Duke of Cambridge is on his way.
The Duchess of Cornwall has also travelled to Balmoral.

In fairness old Lizzie has been hanging on for ages. Can't see the old girl going much longer.