Has the temp in her tank changed? If your house has gotten colder (now that we actually got a winter, jeez...) you might think about a space heater for the room she's in if ambient temps are a problem (that's what I did, way better than trying to keep the temp in the whole house up!)
In any case, make sure the rest of your husbandry is good and she'll be back on feed in no time I'm sure.