Did I see you post that you had elevated creatinine on a recent test?

Are you still taking the Xanax? This is important, because in the short run it works, but as you develop tolerance you will have breakthru pain as each dose wears off. Xanax is a fast acting and quickly eliminated benzo. It can help pain in a way similar to anticonvulsants, and Benzos are sometimes given for seizures too. But when they leave the receptors, then the pain returns until another dose, or a dose increase. It can become a vicious cycle therefore.

Chronic infections suggest low Vit D status. Did you get that tested? Raising low levels, will improve your immunity and may reduce likelihood of chronic upper respiratory infections.

Does the Mobic work for you at all?

Zithromax does not show up on lists for neuropathy. But some papers show that it is not so safe for the heart. There is an increased risk of cardiac death found in new studies:
http://www.webmd.com/heart-disease/h...k-heart-attack
This article cites heart rhythm-- which is a nerve conduction issue in the heart.
http://www.nytimes.com/2012/05/17/he...den-death.html

Twice a year is a higher frequency than normal. But the jury is still out on this new information at this time.

I have not seen Ambien linked with PN as yet.
http://www.drugcite.com/?q=ambien
you can expand "neurological" and see no reports of neuropathy. But with drugs, one never knows for 100% surety.

You might try magnesium supplements, as they often help nerve functions. Take a Chelate type (citrate, gluconate etc) and not OXIDE form. At 1/2 RDA which is about 200mg for adults elemental. Magnesium blocks the pain receptors called NMDA receptors which are activated by calcium and glutamate.
Avoiding MSG in foods may help because of this too. Magnesium often improves circulation too, in addition to helping with pain.