she will yawn a lot, you will hear her weezing, she will stop eating...at least this is what happened when my big boy Fred had one. what we did is put him in a "hot box", a smaller tank that was isolated away from everyone and higher on the heat (kept it around 90) for about 3 weeks and then checked him. If the hot box doesn't work, then take him to a vet.

hope this helps.