Have had 2 episodes of burning/nausea, etc in the past 3-4 weeks.  First time was 4 a.m., woke up needing to urinate.  Went to bathroom, on way back became very nauseous, and had terrible pain in abdomen.  Had to get up after about a minute and woke my husband.  Had horrible burning pain(like an explosion) start in my chest and radiate into my arms and hands and even in my neck. Started w/very sweaty skin but then was cold w/clammy skin.Took BP after about 5-10 mins and it was 198/98.  Everything went back to normal after 15 or so.  I sleep w/oxygen for sleep apnea, so I put the oxygen on. Felt weak & tired for several days.  Had another episode 3 nights ago.  I was relaxing at my computer about to go to bed. I felt very nauseous. Went to the bathroom.  Did not vomit, but I felt the hot (sweaty) feeling start.  My skin was wet to touch. I sent my kids to get my husband.  They wanted me to call 911.  Said my skin was a gray color.  Then I felt the weird "burning start in the center of my chest and go outward to my arms and hands and up into my head.  It is so bad that I was doubled over.  After it subsides, the sweating goes away and I feel so cold and clammy and weak and tired again.  

I am a 44 y/o with a very major past medical history.  I am on BP med, thyroid, Adderall (amphetamine), morhphine & clonodine via an intrathecal pump.with methadone for breakthru pain.  I had a paraganglioma (carotid body tumor) removed in 2002.  I have had bp problems since.  My bp can be very erratic since then.  I did have a heart workup about 2 years ago when I had a severe reaction to a new BP med I took I was admitted to the hospital for telemetry.  Also had outpatient heart tests.  All were ok. 

Is this to do with tbe heart? or could it be a TIA?  Problems from sleep apnea? It scares me so bad.  I had hoped  after the first I would never have to go thru it again.  Any help would be appreciated.  I go to a new endocrinologist this week to see if he can get my thyroid and other problems straight.  Thanks.