Ok, if it is a normal Privet then it is hardy and should not be inside. I would be surprised if the plant does not dry out quicker than that, and I think you should be watering more often. Check with a chopstick if it comes out dry or clean then it needs water. Also when watering put the pot in a bowl of water and wait for the bubbles to stop before draining and putting back. The problem could be a number of things but most likely it is cultural, and will be cured once this is corrected. If it is Chinese Privet, then it is not hardy. You need to know which it is and from the leaves it could be anything,
Geoff.