Mouth breathing and bulging eyes are symptoms of very serious illness. Mouth breathing from a rabbit is essentially an emergency situation. You really need to get her to a rabbit savvy vet right away if you want to have any chance of saving her. I'm not sure if the vet will be able to cure whatever is going on at this point, but they can hopefully at least give her meds to help her feel more comfortable and possibly get her eating better on her own again.
Those symptoms make me think there might be something going on with her heart or possibly even a thymoma. So both extremely serious health conditions.
Until she can be seen by a vet(which needs to be by tomorrow, tell them it's an emergency), I would want to make sure she was getting some food into her. I would make a pellet mush with warm water and syringe feed about 3-4cc/per lb of body weight every 4 hours. Also syringe water. Syringe feeding does need to be done carefully and slowly, giving the rabbit time to chew and swallow little bits at a time, so you don't risk the contents being aspirated. If a rabbit won't swallow the food and just sits with it in their mouth and lets it drip out of their mouth, I wouldn't continue the syringe feeding, as this usually means the rabbit is at a critical stage and may not make it. This video shows how to syringe feed with critical care mix. A pellet mush will be a little bit harder and may clog the syringe tip. If so the tip can be cut off so the opening is larger, or use a larger tip feeding syringe.
[ame]https://www.youtube.com/watch?v=8iGZVYVm5Bg[/ame]