I'm going insane trying to find this book I read as a kid with no luck. It was aimed at probably 8-12 year olds, it followed a young girl from historical England named either Elizabeth or Mary (I think she was implied to be either a young Elizabeth I or Mary of Scots) who had contracted some kind of disease, maybe scarlet fever or pneumonia? The story starts with her sick in bed and she's trying to fall asleep when a beam of light hits her across the face between the canopy of her bed, and suddenly she's in modern day (1990s/2000s) North America. She makes friends with a modern girl her age, and I distinctly remember the main character not understanding that the other girl went by a name that wasn't her "baptismal name" because she went by a nickname, but I can't remember what that name was. The modern girl's father took care of Mary(?) and got her medical care, which I remember being 2 or 3 weeks of antibiotics. The mc spends a long time wanting desperately to go home, but just as she begins to adjust to modern life, she's laying in a barn (I think) with the other girl and the light hits her face in the same way as at the start of the story. She wakes up back in her canopy bed, wearing all the same clothes she was before, except for the muddy tennis shoes she was wearing in the modern world, and the story ends with someone (a nurse or a maid or something similar) commenting on how Mary is "suddenly" better. Please god help me find this book I've been searching for at least an hour and have found NOTHING
