It would be very hard to recommend a medication when we aren't sure exactly what is wrong with her. An antibiotic might do no good at all, or even do harm if it was not the correct one. Most of the time it's not really a good idea to just 'throw the kitchen sink at it' and hope for the best. If you have an avian vet, then getting an exam and xray might help narrow down the possibilities. Even if you can just get a fecal float test done to check for parasites and bacteria it may help. If it is a reproductive issue, and that is what my personal opinion is leaning towards at this point, then most of the time treatment options are pretty limited, and often not successful. Since so many conditions in birds can present with very similar symptoms it can be very hard to determine sometimes. In truth, some answers are not had until after they pass and a necropsy is done. I'm not trying to be discouraging, just my opinions based on my experience. I would certainly give vitamins as recommended above, those will not hurt anything, are not expensive or difficult, and may help. Vitamin deficiencies can happen any time and can often have neurological symptoms, like difficultly walking. Anytime I have a bird with any issue I will generally supplement vitamins just as a matter of course. Likewise, probiotics can help with the immune system, are not expensive or difficult, and won't hurt anything.