Hopefully, you've left WiFi and/or Cellular turned on and registered for an Apple ID. Go to a computer and go to the website www.icloud.com . Log in using your apple id. click on the Find My iPone icon (yes, I know it's an iPad - same difference). You'll have to enter your password again. Hopefully, you'll see a map with a green dot indicating the location of your iPad. From there, you'll be able to play a sound on the device, lock the device, or erase the device. Good luck.