So DD (14 months) has decided after a good few months of sleeping normally (decent 2 hour nap in the day and 11/12 hours each night) that for the past few months she just doesn't need to sleep at night and neither does anyone else! In a desperate bid for some sleep we decided a week ago to cut out her nap in the day and she slept through for 11/12 hours again at night. Tonight through it's all started again. She's been up and down starting at about 10pm this evening after going to bed at 7pm. She's not teething or unwell and my biggest problem is that when she's up she isn't upset she just sings/shouts happily at the top of her voice. She unfortunately shares a room with DD1 (5) and it wakes her up as well. She usually gets up in drips and drabs for 5 minutes then at some point between 12/4am will be awake for 2 whole hours just generally making a noise. I've tried going into her and laying her back down telling her it's sleepy time etc but she just gets back up the second I leave the room and resumes her singing/shouting. I'm at my wits end with her and all the advice I can find applies to babies waking up upset/crying which she isn't so doesn't really apply to her. If she wasn't in the same room as DD1 I'd just leave her to it but it's not possible and it has to stop for all our sakes. What ends up happening at the moment is DD1 had to come into bed with me whilst poor DH moves to the couch. Has anyone else experienced anything like this? Starting to get really depressed about it all as we are unable to move house at the moment and I feel wretched about the affect it's having in DD1. She's constantly tired and moody from being woken up all night. She's not used to it as she's always been an amazing sleeper. We desperately need some help.