Update: 
Okay, I finally got some more information to work with about Bee. Took her to the avian specialist vet, they did Xrays on her, and found that she's got a buildup of fluid in her peritoneal cavity that could either be ascites or peritonitis. The fluid is causing her to gain weight and is pushing her internal organs around, which is causing her to have to work harder to breathe when her heart rate is up. Without extracting a sample, (and extracting more $$ from my wallet), we can't know which one it is, but since she has laid two normal eggs in the past week, I'm guessing that it's ascites. 
They prescribed her Metacam to take for 15 days. But in humans, this medication has been known to cause ascites as a side-effect, and I'm not sure if I want to give it to her.
Looks like a no-fat diet and some milk thistle is in Bee's immediate future, and I'll see if I can't have that fluid drained from her to ease her symptoms. If anyone has any other suggestions to help manage her symptoms, please chime in! I'm all ears.
The office is supposed to be sending me copies of the xrays they took, so I'll post them asap.