There are various causes for Dizziness: Low
sugar, Low Blood pressure, Vestibular (ear related vertigo) imbalance, central nervous system imbalance, BPPV (Vertigo) etc.
First of we need to find out the cause of the dizziness. It is best you consult a General Physician for this and preferably in person so they can see your gait and do postural tests on you as well. The GP then might refer you to a specialist based on the cause.
Next Steps
If it is postural with normal BP you might consider consulting an ENT Surgeon
Health Tips
Drink plenty of fluids, Stay hydrated and energized, Have a biscuit or dry fruits or keep a energy drink available while exercising.