Don't know if you got the PM but I thought Air sac mites. The stress of bird marts is enough to bring underlying things like this to the service. I usually use iverlux but scatt should be fine, though stronger medication. You should see improvement soon like tommorrow,
One problem to watch for, if it is a heavy mite infestation then killing all the mites at once they can clog up the respitory system... lung, sinus infections. If this seems to be the case you may want to start an antibiotic for this like amoxitex or Baytril. But only if she continue to get worse.
The advantage of using iverlux by morning bird or bird health is that it contains slippery elm that help soothes the throat and membrames of the birds respirtory system. Hopefully she will be perkier tommorrow
Notes... she will cuddle for the warnth. If she perks up with the air sac treatment treat the male also. Even if he isn't showing symptoms he has been exsposed.