Digging at the bed doesn’t mean she’s stressed. She’s calmly but determinedly digging because: Bunnies dig up, and claw up, and chew up soft materials to make their own bedding. As someone else said, you need to be sure she isn’t ingesting any, and a piece of fleece or fleece pet mat might be preferable because of it. Bunnies love to fluff up the kind of filler and fibers found in common cat and dog pet beds. That takes some chewing and digging. She isn’t stressed, she’s just being a bunny. As long as she’s not ingesting any of the fluff she’s digging it up into, she’ll probably stop after she’s dug some up and is content with the quantity she’s dug up. My bunnies do a little chewing and digging in their bedding, then they come to a stopping point.
And, water bottles can tend to leak, you have to find one that doesn’t leak. The one i have from Petco.com doesn’t leak and it’s a good bottle.