our 15 wo sleeps thru the nights sometimes even when his day is the same we are on 3 hr easy...breastfeed...is this normal? our first slept thru the night and never looked back now with this baby he sleeps 8-5 or 6 then he eats and goes back til 7/730 2 nights in a row every few nights and the 3rd night will wake as early as midnight, 2 and 5 he eats at 5 the other 2 wakings are not hunger...thoughts?