one of my gouldian hens isn't doing very well tonight, and i'm worried about her. i noticed during the day that she had been sleeping all day. when i came upstairs about 20 min ago to check on her, she was still asleep. i watched her for a bit, and i noticed that she started making regurgitation movements with her head and neck (like when a parrot goes to feed their babies, moving it from side to side). i became very worried when a bunch of liquid came shooting out of her beak, which i assume was vomit (it was clear, like water)

she wasn't puffed up, but her wings were down low at her sides.
i moved her to a hospital cage and gave her a drop of calcium to her beak about 10 min ago, in case it is a calcium deprivation. she has a heat lamp in the cage, and i covered it with a wet towel for humidity. what else can i do for her? what could this be?
she is perched in the hospital cage now, her eyes are closed but she is under the heat lamp, thank God.