I often feel very weak and shaky, often after large meals or if I haven't eaten for a few hours, could this be a sign of diabetes?
It is more typical of reactive hypoglycemia from your blood sugar going low rather than high (diabetes is high blood sugar).
It would be important to check your blood sugar during one of these weak and shaky episodes to confirm that your blood sugar is low (under 70) when you feel like that. Otherwise, if it is normal, you need to have a more thorough metabolic work up to determine what is causing these symptoms. If the episodes last for awhile, we can see you in the Health Center urgently to do the test during our open hours, of you can try fasting overnight (nothing but water for 12 hours) and we can see what your blood sugar is in the morning.Call 650-3400 to set up an appointment for further evaluation. More information can be found at http://www.mayoclinic.com/health/reactive-hypoglycemia/AN00934