Help! My 4.5 month old has been waking at night, nursing, and then won't go back down for another 1-2 hours. I will put him in his crib drowsy but awake, and he instantly perks up and starts playing. He'll do this for 1-2 hours (always between 2-5 am) and eventually cry because he is tired. He'll then scream whether we are with him or not b/c he can't go back to sleep. Any tips for what's causing this and how to help him get back to sleep? He generally goes to bed around 7, and takes 3-4 naps a day. Thank you!!