Most likely a date mess up, or some rabbits wait pretty long.
Give her rest, lots of food (that what she's used to) and water(although 1-2 days before giving birth they often lose some appetite), nestbox and a lot of privacy, and enough space to hop around. Keep an eye on her if and where she builds a nest, give her lots of hay to gather. Really, piles of it, in different locations.
My does build the nest just in time, sometimes a few hours in advance, most times they give birth in the evening, before midnight, but that can differ.
I wouldn't interact too much, just being around to have a look now and then, but give her privacy, leave her alone. That little voice in their head, their instincts, telling them what to do can be too easily droned out. Let her get the feeling that the place she'S in is undisturbed and hers.
When you notice her nesting, check regularily from a distance. If the nest isn't in the nestbox just make sure she has enough hay to build a proper one anyway. When she's done, feed her, check for kits outside the nest.
Prepare an alternative for the case that she doesn't pluck enough for, like cotton wool, drier lint, - I keep fur I brush from them when they molt for such occasions.
You can't change past stress anyway, just make sure she can settle in now. Socialising with her etc. can wait.
Good luck.
