There can be various reasons for your dizziness
and loss of balance,since you are an diabetic and hypertensive for a long time.
The most common causes in you seem to be due to....
Diabetic autonomic neuropathy
You may be having orthostatic hypertension
where blood pressure drops too low on getting up.
Your blood pressure medications may be responsible for your problem
Low potassium levels may also cause this.
Poor nutrition may be causing deficiencies of nutrients in you.
Other causes may be problems with your inner ear or brain.
You must consult a neurologist
and get investigated properly,before proper treatment can be instituted.