has something changed for her (nursery? preschool?)? it seems normal to me, many dc go one step forward developmentally then a step or two back, when they mastered another big skill. I would put her in pull ups (maybe let her choose a pack if she's reluctant).
Not sure, but ride the storm? One of mine I had to put back in pyjama pants. With another one it was just a blip. Has she just started at nursery? I found mine would go through a wetting again blip with extra tiredness like starting school...?