Her Majesty was due to attend a military celebration in Wales during the country's St David's Day celebrations, but was forced to cancel her planned engagements.
Buckingham Palace declined to comment on her condition, but a spokeswoman earlier confirmed the Queen would spend the weekend at Windsor.
More top news
Thursday morning's weather for the west of the region
Thursday morning's weather for the east of the region
Simon's Blog - Faces In Unexpected Places