I was in your situation too a couple of months ago. Best thing is to just keep a close eye on her and see how she goes, try to spend a bit more time with her, and hard as it will be, try not to be upset when your with her as she may pick up on your emotions.
My bun carried on eating and drinking etc, but seemed to stay in the hutch more. I think I projected my emotions onto him though, and because I was really sad I imagined he felt the same, and that upset me more. But someone on here gave me some advice which I think may be true, bunnies may not feel sad in the way we do, but they may just be quieter and less active as they don't have the stimulation of another bunny. I'm sure they do miss the company of their partner bun but maybe don't feel sad about it, it's just different for them. I really hoped that was true because it broke my heart to think of my bunny being sad, as I'm sure it does with you and Fudge.
I've also read on here bout shy buns coming into their own once the dominant partner has passed.
All buns are different, and I think you just have to follow your gut feeling.
We got a new partner after a week, he groomed and happy flopped next to her at the rescue so he was read for more bunny company, perhaps long before I was really.
Bigs hugs x