Drone cells should bee normal. Were the "swarm cells" small cups or longer peanut shaped cells with larva in them? I'm assuming they weren't capped yet. If the cells were longer with larva or capped, the hive is in swarm mode and short of creating a split with your "old" queen and frames of brood to make the hive think it's swarmed, you may be too late. If you saw the queen the cells probably are uncapped since the hive usually swarms before queen cells are capped or as soon as they are capped. I would order another complete hive so you're prepared in case you get a swarm, whether from your hive or somewhere else. The bees do what they want to do in spite of what we do most of the time. Good luck!