That happened with my last draft, "Elinor and Marianne", which I wrote last week about a story Jane wrote in 1795 of the same name. It was an epistolary novel about two sisters, and was later rewritten as Sense and Sensibility. No draft of the earlier epistolary novel survives, so its precise contents are a matter of conjecture. I've spent a few days narrowing the gap on speculation, and have found some excellent resources that enable one to look at parts of Sense & Sensibility to see where sections were probably lifted from an epistolary format (it wasn't exactly a seamless process), and I'm hoping to doctor that draft this week. But I'd really like to get something new on the page today, too.
I suppose I shall see.