Strange light-headed sensations? Problems with fainting?

Hello, I am a 21 year old female, I weigh about 100 pounds and I am 5'4" tall. Lately I've been experiencing strange light-headed sensations. They only last for a mere split second, but I am concerned because I have had problems experiencing spontaneous fainting/dizzy spells my whole life since I was a child. These strange light-headed sensations are similar to that sudden drop feeling you may experience when you miss your step, or if you experience a random dip in the road while driving. They only last two to three seconds. I am wondering if it is any way affiliated with my problems with fainting that I experience. I have only been tested once before for anemia when I was 15 after a fainting spell I experienced where I fainted in the bathroom and took down the trashcan and ripped the  toilet-paper holder out of the wall during the fall (Clumsy me!). The tests did not show me being anemic. Should I be concerned over these fainting spells? Should I be concerned over these light-headed sensations? Should I have another anemia test? Could these issues be potentially unrelated to any blood disorders? Any advice/knowledge on the subject would be appreciated! Thanks!

[Dr Santos]

Hi,
How are you? Pre-syncope usually presents with feeling faint and lightheaded without losing consciousness. Other symptoms like nausea, pale skin and clamminess may also be observed. This condition may be caused by drop in blood pressure or inadequate output of blood from the heart. If it recurs, it is best that you have this checked by your doctor for proper evaluation. A repeat cbc and other blood tests may also help rule out anemia or other blood disorders, which can also recur from time to time. Take care and do keep us posted.