You need to get examined to rule out a few things such as low blood pressure, postural hypotension (fall in blood pressure, cervical spinal nerve compression, hypoglycemia (low
blood sugar), severe anemia, an underactive
thyroid (called hypothyroidism), overactive
thyroid (called hyperthyroidism), adrenal insufficiency (called Addison's disease), GERD or gastric reflux, and internal ear infections.
Do discuss this with your doctor and get yourself examined. Take care!