My baby has completed 4 months she doesn't sleep for too long in the day.... she sleeps for an hour and then she gets up and keep playing and after 1-2 hours she is tired and sleeps again.... is this normal ? and she sleeps for almost 5-6 hours at night so should I wake her up at night to feed in 3 hrs or should I let her sleep for so long..... I feed her every 4 hrs during day time