Hiya, sorry to hear you are experiencing multiple symptoms.
POTS is diagnosed by a heart rate increase of 30bpm on standing or to 120bpm within a ten minute period, the test you would need for this is a Tilt Table Test. Below is a link detailing more about the diagnostic criteria for POTS:
http://www.medhelp.org/health_pages/Neurological-Disorders/Dysautonomia--POTS-Diagnostic-Criteria/show/1011?cid=196
Symptoms of POTS can be many and are often non specific, leading many people to have to search hard for a doctor who knows about this condition and 'spots' the signs/symptoms. Below is a link to a website listing the symptoms:
http://dinet.org/symptoms.htm
POTS patients can experience there own collection of the listed symptoms, or can have unique ones all of their own. A common factor that must be present is the increase of heart rate upon standing. Do you happen to know what yours is like?
May I ask you what testing you have had done so far, there are several other conditions that have similiar symptoms as POTS. Also, what symptoms are you experiencing?
Here is a link to the Dysautonomia health pages, take a look and see if anything sounds familiar to you:
http://www.medhelp.org/health_pages/list?cid=196
I see from your posts that you have a cardiologist appointment this month, you could ask him/her about the possibility of a Tilt Table Test.