Dizzy spells can have many causes, and only one is
high BP. There could be other causes for those dizzy spells like
postural hypotension, cardiac diseases, arrhythmias, vertebro-basilar insufficiency, benign paroxysmal positional
vertigo, vestibulitis, middle ear disorders, anemia, etc.
The BP that you have recorded is abnormal - the systolic BP should be less than 140, and probably the diastolic BP of 51 is a bit low. A pattern like this can be seen in patients with anemia, Vit B1 deficiency,
thyroid disorders, mitral or
aortic regurgitation, fever, etc. Also, sometimes, automated BP measurement devices, if not calibrated well, can give erroneous values.
I think you should see a good physician and get yourself evaluated thoroughly.