Our 21 month old has settled well for naps and bedtime since she was around 10 months old and slept through albeit it waking at 5.30am. By settling well I mean unless unwell we would do bedtime routine, say goodnight, put here down and she would take herself off to sleep. Suddenly five nights ago she woke around midnight screaming and would only settle when someone went in and sat next to her when she promptly fell back asleep. Since then trying to put her down for her midday nap or bedtime is met with immediate screaming and hysterics which go on and on and on until someone goes back in and sit with her. Apparently nursery are struggling with her at nap time as well which was never previously an issue. As soon as you sit down next to her crib she lies down and goes to sleep. At night she has started waking once or twice and again someone has to go in. Is this a phase?! Help are there any tips! We have tried leaving her for a while but it just doesn't stop until you go in. She isn't unwell and isn't teething (recently got her toddler molars and was fine with them coming through). Any advice appreciated or just solidarity in knowing we aren't alone with the sudden shift... thanks