Im not a doctor, but it sounds like blood sugar issues, maybe diabetes
, which can be very serious, I would see a different doctor and mention to him all you symptoms wright it down and hand it to him so he can see the whole picture. In the meantime be sure to keep your blood sugar steady by not going too long between meals and not eating sugary things, always balance a carb with a protien, keep some peanut butter or cheese crackers with you so that you can eat if you go to long w/out food and feel dizzy or sick. If you have serious blood sugar issues all of this is not enough, you need to see a doctor. Also if you are drinking caffiene, you are very young and you could easily throw yourself out of balance by over doing it. Stay away from those energy drinks, the caffiene in them is outrageous, even for an adult. If your drinking those and you stop you might feel worse for about a week and then you should feel better.