My parakeet is dying?

Cracker is my white female budgie, at least 6 years old, maybe older (bought from pet store 6 years ago). She had weird feather issues, bald patches, a stopped posture, and brown crust on her nose. I took her to Vet #1, who pulled a few blood feathers and said the pet store gave her a bad wing trim.

Nothing got better. A few months later, I took her to Vet #2. She said she had Clamydia (?) and gave me cream for her cere. It worked a little, but soon grew back again. She has always had a little wheezing sound ever since.

A few months ago, she started acting strange. She got all fluffed up, didn't want to eat, and sat at the bottom of the cage. I know that means they are sick, so I took her to Vet #3. Vet 3 said there was nothing wrong with her but dehydration, charged me $147 for some meds and water, and sent me home.

She's not better. In fact, she's worse. Now she falls headfirst into the seed bowl and scratches all the seed out without eating it. She goes to the bottom of the cage and frantically scratches like she wants to get out. It's so weird. She hangs upside down and squawks in a weird voice. When out of the cage, because she is hand tame, she tries to hide in dark places which she never did before. She wants to be out and on me all the time. She closes her eyes a lot, but sings sometimes. She goes to the male budgie and makes high pitched squeaking sounds and he feeds her. I've never heard her do this before. Please help!