It is VERY normal. You are strange to him the house is strange everything is strange and scary. Give him time. Let him come out on his own. Leave him alone. Maybe close the bedroom door and leave him for an hour or so then go check on him. If he is still under the bed which he may very well be get down on the floor and talk to him quietly. Offer him some yummy treats. If he doesn't take them from you it's ok leave a couple anyway. Let him explore a little at a time when he is ready. Keep going back and checking on him and talking to him. Try to pet him gently and have yummy things on hand. He needs to know he can trust you and that everything is ok. Time is the key. Keep us posted on his progress. What is his name BTW? When he gets comfy with you and his new surroundings you will have to formally introduce him to the PT gang. And that will mean pictures. We look seeing everyone's beautiful furbabies.