How long have you been on the Aza? I went on that when I couldn't get off steroids - but it took a good three months for it to kick in.
Have you tried any rectal meds to help during your pred taper?
Hang in there and take things a day at a time. If people ask, just say you have a stomachache - I've found most people won't ask past that :) Everyone has had one at one time or another, so they should understand.
BTW - Welcome to HealingWell! Glad to have you :) Sorry about the circumstances though.