it's probably got a bit of shock from the sudden change in temp - it may even have gotten pretty chilled the last few nights it was outside.
do you have it in the same spot as previously (before you put it outside for the summer)? if not, put it back where you had it orginally.
is it getting the same light as it was when it was outside? if not, put it in a spot where it will get the same lighting as it did when it was outside.
it might not need such frequent watering...when they are outside, they tend to need more frequent drinks...
it might need to be repotted too...check for roots growing
out of the bottom drain holes...if there are no drain holes it might be getting root-rot due to the water sitting in the bottom of the pot - again, the answer would be to repot it in something with drain holes. also, let the soil dry out a bit before watering again.
when moving plants
from inside to out or vice versa, it's best to do so gradually - start taking it in/out at night and put back out/in during the day...or just do it when the temp is the same inside and out and you can just move it and leave it...you'll know for next year