Thank you for your question. Dizziness is a common term used to describe a whole range of symtoms including lightheadedness, vertigo, imbalance, spaced out and drowsiness. It is important for you to describe the exact nature of your symptom to your doctor as different types of dizziness have different causes. It is beyond this Q&A section to cover all possible causes of giddiness.
From the history provided, it sounds like your dizziness is triggered by a sudden change in body position ("getting up quickly from bed"). The two most common cause of positional giddiness are:
1 Benign Paroxysmal Positional Vertigo (BPPV) - This is due to calcium depositis or "stones" in the inner ear balance system. When the head or body moves, the "stones" will move and trigger the sensors in the balance system, giving the brain a sensation of the room spinning (vertigo) even though the body or head movement has stopped. It typically lasts a few minutes and may be accompanied by nausea and vomiting. Diagnosis can usually be achieved by a combination of suggestive clinical history and a clinical test called a Dix Hallpike test. The treatment consist of a series of head and body turnings that is done in the clinic (known as an Epley's manoeuvre). This is commonly done by an ENT Specialist.
2. Postural hypotension - This is a condition in which your body's blood pressure drops when you get up from a lying or sitting position. Again, there are many potential causes for this and from the description of your condition, dehydration (e.g from intense exercise and lack of hydration) or low blood level (medically known as anaemia from heavy bleeding from your recent menstruation) may be possible reasons for this. Your General Practitioner can check your blood pressure and blood level (Hemoglobin level) to determine if this is the cause of your giddiness.
Since you have amended your diet recently, it is also important to ensure that your nutrition throughout the day is adequate and you are not suffering from low blood sugar level which can also cause dizziness.
Your should visit a Family Physician/General Practitioner for a start for an assessment. In the meantime, I would suggest moderating the intensity of your exercise and the change in your diet so your body can adapt better.
Hope this helps and all the best!
