Sounds like you may have an autonomic neuropathy issue...which is a component of PN.

Autonomic neuropathy can include BP and heart rate issues as well as difficulty initiating urination, urine retention, and GI problems like gastropareis (delayed emptying--which caused bloating, discomfort, nausea, etc). It can even cause vasospasms, sexual dysfunction, respiratory problems (central apnea), and sweating dysfunction.

You might want to consider autonomic testing.

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