Please visit the Dysautonomia (autonomic dysfunction) community pages.
I have all symptoms and an endocrine disorder was suspected but all tests were found to be ok. I have an adrenal tumour but this does not look to be functioning. I have 'suspected' Postural Orthostatic Tachycardia Syndrome (POTS). It is an orthostatic intolerance, meaning the body cannot tolerate being upright. Although, symptoms can be present whilst laying.
It is diagnosed through a tilt table test and diagnosis criteria is a heart rate increase of 30bpm or to 120bpm upon standing (within 30 mins). There are many symptoms that can change on a day to day or hour to hour basis, some being: heart rate increases, palpitations, bp drops/rises, dizzyness, nausea, flu like symptoms, breathing issues, chest pain, blood sugar drops, malaise, weakness, fatigue........there are more and they can differ from person to person. They can come in episodes to.
Below is a link to Dysautonomia health pages:
http://www.medhelp.org/health_pages/list?cid=196
A link to dysautonomia forum:
http://www.medhelp.org/forums/Dysautonomia-Autonomic-Dysfunction/show/266
It is worth taking a look to see if any of this sounds familiar to you x Let me know if I can help in anyway.