Dizziness in relation to blood pressure probably has more in common with low pressure than actually high blood pressure.
From that point of view, it could be a serious problem and in many ways the fact that you're suffering from dizziness and potential drops in blood pressure are probably more important than the levels to which the blood pressure drops to so your doctor should get to the bottom of it if it is indeed a regular occurrence..
For some insight, usually dizzy spells occur as a result of changes in your blood pressure from moving from low blood pressure to high blood pressure as an example when you first get up in the morning as it is a known medical fact that your blood pressure is usually lowest at night and rises sharply upon waking.
"Also, you can suffer dizzy spells when your blood pressure drops sharply as a result of dehydration, blood loss, allergic reaction, postural hypotension, etc, The dizzy spells could be brought about by what is called postprandial hypotension; this is usually an occurrence that affects older adults with high blood pressure or what could be best described as autonomic nervous system disorders such as Parkinson's disease and basically occurs after meals".
Regardless, if you are experiencing on a regular basis any dizziness then you need to see your doctor as soon as you can to rule out anything serious. .
Hope this helps, and thanks for the question. If you have any followup questions, feel free to respond, take care.