I hope you find him soon. What room is he housed in? If he's housed in your room, check all his familiar exploration spots, spaces where he can hide, and don't panic. He'll turn up sooner or later. Do leave something in case he wants to eat. I've temporarily lost Melody when she decides to leave her pillow. She'll be either under the bed or in a place where she thinks she can find a place to hide and make me worry. Check everywhere. He's exploring places.