Im 26. Ive been tested for diabetes and that came back negative - but every day at some point, my hands and my arms shake, I feel weak and as though the blood rushes from my body, I tend to suffer with panic attacks which i am starting to learn to control, so when i start to shake, as long as i keep calm and take deep breathes I manage to get myself something sweet to eat or drink eg ice cream or cola then after a couple of minutes i stop shaking? - if i cant get to anything i have to go and lie down and then it ends up in a panic attack and im in a right state if im honest, what does this mean??

Consult another doctor about this problem, perhaps begin monitoring your blood sugar. You may not have diabetes, but you may have issues with hypoglycemia, so definitely investigate some more.

It definitely sounds like a drop in sugar levels. Check with your doctor. Are you eating a balanced diet? You aren't skipping meals are you? Make sure you are eating enough protein.

Have you been checked for an iron or vitamin deficiency? It does sound like a drop in sugar levels or even hypoglycemia.

Follow up with your doctor. In the mean time, keep a log of when this happens. Leading up to it... did you eat? If so, what? Are you drinking plenty of fluids? Are you stressed? What time of day? Try and log everything happening around these episodes. It could also be a physical manifestation of a panic/anxiety attack that could require more professional assistance to handle.