My 9 week old baby started, of her own volition, sleeping through the night this past week. She usually goes to bed at 7-8 and wakes up around 4ish, and again at 7. Is that ok? I'm feeding her on demand and she seems to be doing really well, gaining weight and diapers are great, though she does get really fussy in the evenings. Is it ok for her to be sleeping this long? Is she getting enough to eat? I'm afraid my supply is going to dip now that she's sleeping so long. I know this is "supposed" to be a good thing, and yes I'm loving the extra sleep, but I guess I just need some reassurance that this is ok.