I'm hungry!

Legitimately stomach-growling hungry and I can't figure out why. Normally at this point in the day I've eaten all my usual food with the exception of my yogurt--I usually eat that around 4:00 when I eat it at all. But today I've had everything I brought with me (although I had cottage cheese and fruit instead of yogurt) AND two Pepperidge Farm cookies from a tray in the kitchen and I'm still hungry and it's only 3:30. How can I last another hour and a half without eating more cookies or hitting the vending machine?