If she has a stuck egg - no amount of tums is going to help her. Can you take her to a vet? Please post in detail on the "emergencies, diseases, injuries, cures," thread - this bird needs diagnosis and help NOW!!
Sounds like Ascites. Like a water balloon in her belly. Fluid builds up in the belly, usually from heart failure or hypertension. There is usually no treatment and eventually the bird needs to be put down. I am so sorry.
Alright
You have received some very good advice here