I have periods when I wake up just after dropping off to sleep or maybe later when I wake up feeling nauseous with tension around my neck and a pronounced heart beat which tends to be faster than normal. Unable to go back to sleep as the whole scenario is repeated although by staying awake I seem to be able to lessen the symptoms. I have always been an anxious person and tend to jump at the least thing. I am 65 years old weigh 168lbs; inoperable brain stem astrocytoma diagnosed 2001. Mild Heart attack Feb 2002. Bladder polyps removed 2005.