my 3 week 3 day old usually bf every 3 hours for 15 minutes on each breast. Now it seems he is feeding every 2-2.5 hours for 10 minutes at a time on each breast. I have tried waking him up to see if he will bf longer and no luck. He falls asleep each time. Is this normal for this age? Should I be concerned? He is latching properly and milk is coming out easily for him. Or is this a temporary growth spurt?