Whats happening when your body is shaking uncontrollably?

It could mean a number of things, depending on what age you are. It's important that you notice when it starts to happen. If it is constant, then you should see a doctor promptly. If it is after something intense, such as a workout or a fight, etc. then it is adrenaline working through you. Are you diabetic, or have your blood sugar levels ever been tested? When your blood sugar levels get too low, that can cause your body to shake or tremble. If you start to feel shaky and extremely hungry at the same time, you need to eat something immediately. Also, have you recently begun taking any new medications? This can sometimes be a side effect of some meds.