It can be a sign of weakness when they let their head hang when sleeping. So concerning if she hasn't done before.
Unfortunately I had 7 burds sick , so I gained a lot of experience ...and witnessed different symptoms. My Green cheek let her head hang when sleeping when she was sick, she didn't do that before or after she recovered. My vet told me was weakness.
Moving can just add a little stress to birds and that can allow things to flair up. I can tell you that a number of times after a move people have had their birds get sick.
So as we can never know the only advice we feel safe giving is for people to have them check out. Hopefully all ok, but if not they can get in a bad way quickly.
Things you can do to help, offer millet as a high calorie snack. Offer spinach , and whole leaves of romaine lettuce to nibble on. The nutrients boost helps. As does bell pepper try for tge yellow or orange or red ones fir more vitamin A.
Aldo keeping things warmer. Heat helps them save calories and heal better. So don't have them near a window or draft, turn up heat in home a couple of degrees to 74f. K&H sells a cage warmer panel they can snuggle up to for added warmth.
