The day before my R. stalli laid an ooth, she was extremely restless, and seemed to want to claw her way out of her enclosure. I let her free range on my table, which had both live plants and fake plants and an assortment of random objects. She also didn't eat for two days, and I was afraid to feed her because she seemed to be about to burst at the seams (she's always been eating too much). I hope your mantis isn't eggbound? Also, is she still eating and passing waste normally?
I've read somewhere that you can take a pile of sod with grass, roots, soil, and all, and place it in the enclosure to make the mantis more "comfortable." But I've never tried it myself, since I am always a bit paranoid of pesticides and unwanted critters hiding in the soil.