My almost 7 week old has very impressively started to do a 5-6 hour stretch; however it is from 6.30/7 until 12ish. I was just putting him for a nap at this time but now when I've finally got him off to sleep he hasn't woken. Is there any way I can move this longer sleep to 11-5ish or is there nothing much to be done? He wakes at 3 and then 6ish after this