You may have something fibromyalgia or chronic fatigue syndrome and a condition that sometimes comes along with those two disorders called orthostatic intolerance. Orthostatic intolerance refers to dizziness and other symptoms upon standing and is a complex condition that is usually cause by poor blood pressure regulation and/or rapid heart beats. This condition, unfortunately, is not particularly well known. 

You might want to try the National Fibromyalgia Association or the CFIDS Association of America to find a doctor near you that knows about these conditions. 

Here are some links to learn more about orthostatic intolerance

http://en.wikipedia.org/wiki/Orthostatic_intolerance

http://aboutmecfs.org/Trt/TrtOILiving.aspx

http://www.cfids.org/webinar/cfsinfo2010.pdf

Good luck! You are not alone!