No its not normal to lose that much weight in this short of time.
Do You keep records of pee,poops at all?
Weight loss like that in a month could lead to internal parasites taking away from her nutrients.
Few dosings of flagyl either way would fix the feedings as its a food stimulant and also kills many types of parasites. When given proper dosage it will do no harm to snake.
I have been keeping records of all her pees, and poops. She did give me a weird light lime green poop once. What would be the dose for the flagyl?