What's the Name of That Book??? discussion

I hate this feeling like I'm possibly nuts and made this book up in my head. But I didn't! I could have sworn I read it in college but I can't remember if it was for my Women's Lit course or my Civil War courses.

It is set either just before and directly during the Civil War. A "white" woman (possibly only passing, possibly entirely white) is about to inherit property, but her uncle or some equivalent male relative wants to inherit instead. So he finds/forages paperwork to prove that the woman has "slave" blood in her from her xyz grandparent and because even a drop of African American blood makes you no longer White, he sells her into slavery. The story follows that trauma and her basic survival, as well as when she is "freed" and moves, I think, a little North. Because she's educated, she actually starts a small school to teach African American children, but the town she's in is so heinous that the jerks burn the schoolhouse down, and it was the only thing in her whole life that made her happy since losing her parents.
I remember nothing else. This is driving me nuts. Ideas?

I read excerpts of something similar at university but I don't know if all the details match. I do remember the professor talking about the "one drop rule". The book is Iola Leroy: Shadows Uplifted by Frances Ellen Watkins Harper.

Here's the Google Books preview of Iola Leroy: Shadows Uplifted by Frances Ellen Watkins Harper - Mai's suggestion - https://books.google.com/books?id=PKE... There are different cover images.

Y'ALL ARE MAGIC. THANK YOU.

Awesome! You're officially not nuts and you didn't make up the book in your head :-)