I dont really know the signs; but i do know is that if they get too cold, they can go into hibernation - and people sometimes mistake them, thinking their hammy is dead :/
If the air con was on quite alot it could be - seen as you were freezing yourself.
It sounds as if she was cold; but i thought maybe she might of became ill but someone else will give you more help
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Rest in Peace My beautiful Lucky, Fidget, Milo and Sandie<3