My DS is seven weeks old and all of a sudden is sleeping a lot more. He used to eat about every two hours and then take one long stretch at night (~6 hrs). After eating we'd usually play for a while before he'd get tired and go to sleep. Yesterday and today he's been eating more like every 3 or 3 1/2 hours and gets fussy shortly after until I put him to sleep. Do you think he's just having a growth spurt? Or should I be concerned?