I always feel light headed , what could it be , it's not dehydration i drink water all the time?

Multiple causes: If you are drinking excessive water, your sodium may be low. You should see your doctor to evaluate for this and other causes.

Endocinology: Lightheadedness can come from many different causes. If you are drinking a lot, it may be a hormonal issue. Consult a primary care doctor who can direct your care. A good history and physical exam may reveal a simple cause. http://vipplasticsurgery.com.