2yo DS has been an angel sleeper most of his life (7-7, no waking!), then all of a sudden, the week after his second birthday, he won't go to sleep till nearly 2 hours after bedtime, wakes up 3 or 4 times through the night, and wants to get up at 5am.
Nothing's changed routine-wise. What on earth is going on?! And how do I fix it now he can get out of his (big boy) bed??