You may be hypoglycemic. My little sister had a lot of the same problems as you when we were younger. She would eat a lot of food and not gain any weight, after she was done eating it would make her extremely hyper and she would bounce off the walls for the rest of the day. If she didn't eat when she needed to she would get dizzy spells or even faint sometimes. Hypoglycemia is basically when you have really low blood sugar, it's pretty much the opposite of diabetes. My sister would feel horrible if she didn't eat for hours I don't know about the headaches, but i'll look it up for you too.

These are some of the symptoms:
* nervousness,
* sweating,
* intense hunger,
* trembling,
* weakness,
* palpitations, and
* often have trouble speaking.


Or you could have a certain kind of Diabetes, there's 2 different kinds.
Common warnings signs of diabetes include:

* Increased thirst
* Increased hunger (especially after eating)
* Dry mouth
* Frequent urination or urine infections
* Unexplained weight loss (even though you are eating and feel hungry)
* Fatigue (weak, tired feeling)
* Blurred vision
* Headaches
* Diabetic coma (loss of consciousness)

If I missed any of your symptoms you can go to MedicineNet.com and type in your symptoms in the searchbar on their site, just seperate them with a comma.

I hope I helped you with what you were looking for.