There are a few methods of calming that you could try before resorting to calming aids, such as ensuring your cat has a cozy hideaway spot that is just theirs. Cats need to feel safe before they can properly settle down, so ensuring they have an area that they can hunker down into if they need to is paramount. You could also try bringing their essentials closer together - keep the litter tray within easy travel distance (such as the next room) and have their food close by their bed so they don't feel too exposed when trying to get something to eat. If all else fails, there is the option of calming aids which come as either chewy treats, collars, or plug-ins.