Try eating protein about 3-4 hours before you ride, changes how your body metabolizes energy. I agree with Thelka McDaniels, learn about metabolism, you are changing your habits quickly (YAY!) and that's changing your metabolism, and you are craving accordingly. Oatmeal and raisins is very good complex carbohydrates to crave, but craving carbs right after you ride means you burned a bit more than your body had right in easy reach, and it needed a fast top up of energy. Adding protein earlier, so it's digested and available when you need it in mid-ride might help you not bottom out and need the top up.
"I had a very specific craving for a big bowl of oatmeal with raisins."