Thanks for your query. Its common to have this type of occasional symptom, please dont worry. I suggest you take lot of water, and eat frequent means, get your sugar checked and see if you are having hypoglycemia
in between. Always keep some choclates handy, if you feel giddy just pop it. And get your HEMOGLOBIN
I hope this information has been both informative and helpful for you. In case of any doubt, I will be available for follow ups.
Wish you good health.