My little boy was an amazing sleeper, even settled himself. But two weeks ago he started teething, back teeth, four at the same time so he was waking up screaming in pain in the middle of the night. We think the pain has now passed and he just wakes whinging and standing at the edge of the cot, wide awake! The only thing that will send him to sleep, 3 hours later is some milk. Any ideas why this is happening? Thanks in advance!