S.L.
Sounds like she may be going through a growth spurt? Try to increase the amount of food she eats throughout the day - whether it be larger meals and/or more snacks - and continue with a small snack before bed. Eating in the middle of the night is an unhealthy habbit to get into. You're not doing any real "damage" by letting her have those few crackers in the middle of the night but you don't want her body to become dependant upon needing food in the middle of the night. Best wishes!