Stay up really late one night and turn off all the lights. Take a flash light and sit in each room and listen. Look under everything and in dark spots. Close doors behind you after ou have searched that room. Just some tips. If you can, get everyone in your house to look. I know one guy who lost a baby and didn't find them for like a week! Then one night when he was sleeping he woke up and the cresty was on his wall right beside him. You'll find him! I hope you don't have cats or dogs!! Good Luck!!