My 5 month old does the same thing! From about 5:30 onward he nurses pretty much straight. It seems to me he doesn't wake up enough to get a good nursing in and keeps nodding off. I do too though! Probably if I got him up and played with him a bit and then nursed him he'd get a bit more breakfast and have a nice long snooze but as if I'm gonna get him up to play at 5:30 in the morning!! Sometimes if I move away from him he sleeps better. Then when his brother comes and gets me up at about 7, the baby snoozes away 'till nine sometimes. I think it has to do with the mama's milk being out of smelling range.