My six and a half month old has just thrown his routine out the window and has not done the same thing twice in weeks. He previously was like clockwork day and night. He has slept 11-12 hours at night since 10 weeks old and has had 2 regular day sleeps. He is still sleeping through the night but sometimes goes 6-7 hours without sleeping during the day but seems happy to be awake. He cries if I walk out of the room and seems to have been teething for weeks now but nothing has appeared. Has anyone experienced sudden changes in their baby at six months? Tresillian says to perservere with getting him to sleep during the day but he just does not seem interested at all in sleeping.