Sounds like the last thing you want to deal with after such an awful day – first be glad that you are ok.
The simple answer is that a significant and/or sudden shift in behavior that is so readily noticeable means your bunny very likely needs to go to the vet as soon as you can get her in - first thing in the morning if possible. You can usually call 20-30 minutes before they open. Until then, monitor her eating and drinking habbits. You can also switch out her litter box to begin monitoring what she does in there too. You can also do yourself and the doctor a favor and collect a few of her droppings in a ziplock for testing – just stuff ’em in your pocket 
It could be anything. That’s part of the stress of owning a rabbit. Is she eating or drinking? Does she have a proper diet? Heavily shedding? Offer her favorite treat and see if she’ll accept it. If she’s eating normally, then breathe a sigh of relief – that’s a good sign. But it might be good to schedule a checkup in the next day or two anyway…
Life has a way of piling it on all at once, doesn’t it. Prioritize and take a deep breath and you will be ok.