Give her nesting material (soft hay, lots of hay), and, if she hasn't already chosen a spot for the nest a nestbox. It's not too bad if she doesn't have a nestbox when the nest is well insulated or inside.
If she doesn't pull fur you can gently pluck some from her chest, it should come off easily, or use dryer lint ar the like to beef up the nest insulation.
If there is a buck nearby remove him RIGHT NOW.
More information will bring better answers, indoor/outdoor rabbit? Current weather where you are? Your housing setup? Etc. Anyway, stay close, look after her regularly, 15 min intervalls I would say, - if kits are dragged outside the nest you can save them before they freeze. If you find one cold warm it up. A kit is not dead unless it's warm and dead.
More info will get you better answers.