Constant headaches and shakiness can be symptoms of hypoglycemia. There are other illnesses that could cause these symptoms as well, and for proper diagnosis, you should consult your physician.
Low blood sugar is a common cause for these symptoms, but that doesn't automatically mean diabetes. It could also be hypoglycemia, low blood pressure or anxiety attacks. All three can be treated and monitored easily.
This could be either because of bad teeth or due or low blood pressures also. This could be due to the collection of fluids in the ENT glands. It could due to lack of having sufficient water during the day. It could be due to an existence of a tumor also.
Headaches are caused due to tension , noise and alergies to something in an environment. If it occurs constantly, then it produces shakiness. If headache is cured, automatically the shakiness is cured.