Princess Anne was hospitalized June 24 after sustaining a concussion relating to an incident with a horse at the Gatcombe Park estate in southwestern England. She reportedly suffered amnesia and cannot recall the circumstances surrounding her injury.

“This is exactly what Zara’s been worried about happening for years now, but her mom hasn’t had a chance to slow down with everyone else falling apart,” a source told OK! Magazine.

The scare comes as Anne has taken on more royal duties to help her brother, King Charles III, during his cancer treatment, and to fill in gaps left by Princess Catherine as she takes a leave from public duties while undergoing chemotherapy. Anne has long been regarded as the hardest-working member of the royal family, regularly taking on more than 500 official engagements each year.

“It’s really shaken Zara to the core and she’s desperately hoping this memory is temporary,” the OK! source said. “This has been a huge wake-up call for everyone in the family and they’re rightfully distressed.”

Anne was discharged from a hospital on June 28 and is expected to make a full recovery, but details about when she’ll be returning to royal duties are unclear.

“We are both profoundly grateful to the medical team and hospital support staff for their expert care, and to the emergency services who were all so wonderful at the scene,” said Anne’s husband, Vice Admiral Sir Timothy Laurence, per the Daily Beast. “We are both deeply touched by all the kind messages we have received from so many people near and far. It means a great deal.”

Royal biographer Christopher Anderson previously described the incident to the Daily Beast as “nothing new for Anne,” who has been riding horses since she was a child and who competed in equestrian events at the 1976 Olympic Games.

She’s “sustained all sorts of injuries in the process,” Anderson said. “All manner of bruises, fractures, sprains, dislocations, and concussions go with territory.”