You should join us in the Dysautonomia (Autonomic dysfuction) forum here
http://www.medhelp.org/forums/Dysautonomia-Autonomic-Dysfunction/show/266 you'll find POTS is very common in the forum and members go through alot of what you are. In the welcome post there's alot of useful information about ANS issues and doctors etc.
Yes, POTS or postural orthostatic tachycardia syndrome is unfortunately not uncommon. It is a problem with the neurovascular axis (or the communication between nerve receptors and blood pressure response). Primarily, it is a problem where blood pools in the leg during postural changes, most notably going from either a sitting or supine (lying down) position to standing. When this happens abruptly, blood will pool in the gravity dependent parts of the body (i.e. legs) which will often cause an nervous system response for the heart to speed up in order to maintain adequate blood flow to the rest of the body.
Unfortunately, there is no absolute "cure" for POTS, and as you mentioned, is primarily addressed through a number of behavioral modifications including increasing salt and fluid intake, compression stockings, avoiding medications/agents that can exacerbate the condition (certain blood pressure medications, alcohol, etc.), and taking one's time when going to a standing position. There are certain medications that can be used adjunctively to help increase the blood pressure (midodrine) which may be employed if the response is drastic, or other methods have failed. As with any medications, there are always certain side-effects that may accompany them in a select group of people.
POTS has also been associated with CFS (chronic fatigue syndrome), especially in younger aged patients, which might also explain the other symptoms. If you have tried some of the aforementioned therapies and are still having problems, you should speak with your physician about how you can improve on these items. He/she may ask you to keep a daily log of your fluid/salt intake and to record times/places when they are occuring to help asssit you.