That 8 day watering interval was too long an interval, it is not a succulent. It likes more moisture, likes to be on the moist side, warm temps and full sun, but still with well draining soil. Like most citrus plants, moist side with high humidity.
Position it in part sun outdoors to acclimate, like in morning sun position, then maybe after a week to more full sun. It has been growing indoors, so it will need to adjust to the change in light levels and temperature.
