Edema and other symptoms

I hope you can help, I can't believe there is no answer to this,  in the last few weeks i've begun having periphreal edema in my lower legs, ankles, and upper feet....  

Symptoms for 6-8 months have been unusual fatigue, tightness in chest, short of breath with exertion,  waking up at night short on breath,  weakness and nausea.     The symptoms are quite bad and have been unexplained...I've had a normal Thallium stress test,  echo, chest xrays, BNP blood test, CBC, Blood chemistry, Bilirubin/Liver panel,  Thyroid test.      Everything is within normal limits.

But, with the symptoms and the edema together, I cannot believe this picture as a whole isn't frightening,    what does all this tell you?      What disease might I have?     I am only 30 years old and have never, ever had edema before.

[Douglas Bogart, MD]

You might have sleep apnea which could produce your symptoms.  Also you should have a check to make sure you do not have protein in your urine.

[ajbidi]

Do the tests I mentioned rule out all kidney, liver and heart diseases that could cause edema?   What about other problems?  Please help, what needs to be looked for?
I know they say edema is non-specific,  but combined with my symptoms it seems pretty specific to me!