Diabetes is called as silent killer disease because people suffering from it generally feel no symptoms as in your case.
However you must control your diabetes meticulously as uncontrolled diabetes
can lead to various complications involving heart,kidney
,eyes,nervous system etc.
Adopting healthy life style and doing regular exercises is very important in controlling diabetes,however if they prove to be insufficient to control your diabetes then you have take anti diabetic drugs whether oral or parental.
Light giddiness may be early warning to you as it can be because of hypertension
or cervical spondylitis
You must consult your doctor and get a thorough check up and take proper treatment.