This morning when I went to feed the birds, I noticed something was wrong with Peanut. She seemed to be a bit un-coordinated, stumbling and unable to hop. Her flight was weird. She was fluffed up when I took her out of her cage, but I had hoped it was because she was happy to see me (she fluffs up when she's happy) or maybe just warming up. Her voice was definitely odd, and she kept making these low noises. I gave her some millet, which she loves, and right now I'm at school.
I plan on calling the vet when I get home, but I doubt we'll be able to go today, as my mom works late. I'm really worried about her- I've never dealt with a sick bird before and I'm really worried I'll find her...
What can I do for her while she's at home? And what could have caused the sickness? As far as the other birds go, Steve and PJ are fine. Should I quarantine Peanut?
I'm just so worried that I'll find her dead.

I'm hoping that we can get her to the vet today, but I doubt it. And what I'm also a bit worried about is the price- we are a bit tight on money and I'm worried it will be super expensive.
Thank you in advance!