This is the number for JFK lost and found:
JFK airport Lost & Found Services:
(718) 244-4225
(718) 244-4226
If you let me know the airline you were on I'll lookup their lost and found number for you.
Your only hope is that the camera was found by someone honest who turned it in. Do you have the box of the camera? Having the box means you'll also have the exact model and serial number of it, which will make retrieving it much easier.