Well - how much did you water - one time til it came out the drain holes? Two times? What?. Did the water drain quickly or is the soil still soggy - that would be a case of bad (peaty) soil. Does the plant look better? Was the soil very dry to begin with? Indoors unless you're in the south or California.

Stick the plant as close to the window as possible. Plants like a lot of light. Incandescent bulbs and or flourescent bulbs barely provide what plants require to survive. If the plant doesn't get any direct sun light during the day, it will look sickly at some point.

In regards to lighting, a small fluorescent fixture (I'd recommended at least four T8 tubes, if you're using one of those 2-foot types) positioned about an inch above your tree will give you enough light. You don't have to worry about it scorching your leaves, since fluorescent bulbs are so cool. This is especially useful if you don't have a south- or west-facing window to give your tree the natural light it would prefer. You should keep the lights on as long as possible each day (up to 16 hours)...but still give your tree some nice dark time to rest at night. In any case, your tree is probably just becoming acclimated to the indoor environment. Trees were, after all, meant to grow outside. Lighten up on your water a bit until you notice new growth. (Fewer leaves means your tree needs less water...and too much water will drown your tree. You'll notice you're over-watering if the leaves begin to turn pale greenish-yellow.)