I constantly crave sugar and know that this is symptoms of diabetes, but could something else be the cause?

I don’t know what is wrong with me. I constantly crave sugar. So bad sometimes that I will go in the kitchen and eat tablespoons of raw sugar at a time. I am really moody. One minute I will be happy and then 10 minutes later want to cry. I get so sleepy after I eat, especially lunch. But after an hour nap, I feel OK again. I am constantly thirsty and urinate a lot. I am scared because diabetes runs in our family. I am 20 years old, weigh 115 pounds and my height is 5 feet 5 inches. I know that some of these are symptoms of diabetes, but could something else be the cause?

I would suggest you contact your doctor. You do have some symptoms of diabetes with excessive thirst and urination. If you do have diabetes, it can be controlled with a diabetic nutrition therapy, exercise and perhaps medication (either oral or injected insulin).

There is no explanation for why you are craving sugar. Are you eating enough
protein (meat, poultry, fish, eggs, cheese,
milk and dried beans)? High carbohydrate foods induce sleep as well as elevate your mood. Do you eat several high carbohydrate foods at lunch i.e. starches or sweets? Do you feel happy after eating sweets like sugar?

Your mood swings though should be evaluated by a psychologist. But first, I would suggest you see your medical doctor who can evaluate your physical symptoms.