Hungry at night, cramps and belly movements?

Could any of this mean anything? The belly movements actually feel like a baby squirming and kicking! I'm on the coil and not due on, definatly not pregnant as I had a test had the doctors because the movements were scaring me. I eat during the day and can have a huge dinner but feel sO hungry again after a couple of hours and no matter what I eat it doesn't fill me up. Any clues as to what's going on?