If I’m understanding you correctly, she had the surgery, then stayed at that vet’s hospital for boarding, and when you got her back she was much worse. If the hospital she boarded at was the same one that did the surgery, they may have had something go wrong that caused her to be worse (that they aren’t admitting). If that’s the case, or if you just want some other option, I would take her right away for a second opinion at another rabbit savvy vet near you. If they were not responsible, the second vet can tell you if it’s unrelated to the surgery.
And a second vet may have a better prognosis for her recovery and give you more options if there are any. This is very serious and needs a vet’s attention immediately, but you could opt for another vet so you have more opinions to work with. You can find rabbit specialists in the yellow pages under Exotic Vets, so just call first to ask if they handle rabbits before you go to find one that is good with them. Don’t delay.