Strange Dietary Habit - Someone Help!?

I am a regular, 45 year old woman, and recently, I have begun eating crayons. Not just sneaking a few here and there, I have been eating boxes and boxes of crayons every day. Is something wrong with me? Nobody in my family has something like this, I've tried to stop but my cravings are getting even more intense and the habit costs a lot of money. I have no idea why I have these cravings or why I'm doing this. Can somebody please help? I have two children, and neither of them are aware of this.