Rehydrate yourself with sufficient fluids. Take a light carbohydrate snack before you start running to give you energy. A fruit platter, a glass of juice or a milk shake can give you energy.
Check if you are having salt loss due to heavy sweating which can cause these symptoms, you would need to take oral rehydration salts with water on some occasions.
The cramping is due to lactic acidosis and for this you have to eat healthy and acclimatize for running and not to rush upon by going for intense practice.
What kind of diet do you recommend for a young athlete like me? I would go to a dietition but I don't have the money for it.
You would need a good mixture of protein and carbohydrate.
Start your breakfast with carbohydrates dominating in your diet and lunch with proteins dominating in your diet; which is usually after your workouts. Your dinner can be a balanced meal.
Breakfast should contain fruits, salads, brown breads, cornflakes, milk, eggs, juices, shakes and nuts.
Lunch can be soups, meat, fish, chicken, pork, some rice/cereals or breads with adequate salads.