My DD is just under 19m. We had sleep pretty nailed, bedtime routine, down in cot, self-settling without me staying with her, sleeping through. All great. Then out of nowhere about two weeks ago - bam. Suddenly really struggling to self-settle - it can take an hour or even more to get her to drop off and requires me to go back and cuddle her til almost asleep repeatedly. My evenings are non-existent. Does anyone know what might be causing this and what the best approach is? I have tried being firm and saying it's bedtime and lying her back down but she gets totally beside herself - it's not doable. Any advice gratefully received!