Brief Answer:
Dizziness is a difficult problem

Detailed Answer:
Hi,

There are 6 main components to normal upright sensation:
-cardiac: high or low heart rates cause perfusion problems
-blood pressure: low or changing flow with posture causes difficulty with brain function
- vestibular: senses change in head position
-neck: nerves give the brain position sense in space:
-eyes: sight gives visual cues towards orientation
-feet sensation: sensory input on position

before we can try to further narrow the list try to answer some of the following:
- in the beginning did you have an rotational sensations
-do you have numbness/tingling in your feet
-do you have weakness in your legs
-do you feel better lying down than standing up
-is it worse in the morning when getting out of bed than the rest if the day
-is your vision worsening
-do you have neck pain
-does it worsen with neck movement
-are you in blood pressure medications
-have you started any new herbal or over the counter medications

Regards,

---