I agree, sounds very much like stress. Get her checked out with the vet to be on the safe side and if it comes back clear, it is likely that stress is the cause. When cats move house, they are in neutral territory and have to rejig the pecking order again. This, along with being a new environment, causes stress to build up. Plugins are definitely worth a go, and lots of fuss and attention to keep her chilled out. If it continues even with plugins, I would recommend starting right back at the beginning and do slow introductions.