Sleepless in Manchester

So why won’t my child sleep through the night like she’s supposed to?? I’m starting my tough love phase I think. She went to bed around 8pm and slept until 1am. I tried letting her cry herself back to sleep but no luck. Checked on her and she had a dirty nappy so I decided to change her even though it say here not to change a nappy in the middle of the night. I thought maybe she was awake because she had poo. She’s awake and I held her for about 20 minutes and finally decided I should just put her to bed and she’d fall asleep eventually. That was 30 minutes ago and after screaming, moaning, quietness,more screaming and now moaning she is STILL awake!!!