My just turned two year old was always an excellent sleeper after 4 months old, happily going to bed and staying there even through transition to adult bed. The past 4 days he has refused to lay down for naps or bedtime. As soon as we put him down he gets up and cries at the gate that is in the door. Do we just let him cry it out so he realizes it’s time to sleep? We tried going in every 10 minutes but that just made him scream more.