Why do I fall asleep, uncontrollably and my hands/arms go numb!

I was diagnosed with Severe Obstructive Sleep Apnea about a year and a half ago.  I was falling asleep driving to work in the morning, even after a full 8 or 9 hours of sleep.  I went to a sleep lab, and in the first four hours of the test I had 187 obstructive apnea's....they put me on a cpap for the remaining 4 hours of the test, and I immediately fell into REM sleep.  Back at that time, I was prescribed a cpap machine (nose mask) and immediately felt better.  I was able to continue working and had energy levels similiar to those prior to the apnea.  Now a year and a half later, I found that I was falling asleep in the afternoon while working at home.  I'm a computer programmer with a home office.  Mid afternoon I would have to fight to stay awake, and eventually the sleep would win...I'd fall asleep for 1/2 hour to 1 hour or so....sitting upright in my office chair with arms at my sides.   When I awake, my arms and hands are completely numb and they have fallen asleep too.....I went back to the doctor, and the sleep lab sent me home with a cpap that would adjust its pressure based upon my need, and record the events for 3 nights.  After this test they increased my cpap pressure from an 8 to 13.  I was also prescribed Provigil to help with my energy level.  This worked fine for awhile but I am still finding that once or twice a week, I have the 'sleep issue' during an afternoon.  It is so frustrating as I have absolutely no control over it at all.  And it is so odd, because just an hour or so before it happens, I will be fine with no indication that the 'uncontrollable nap' is about to occur.    
I require focus and alertness to perform my job - complex computer code and coordination of changes....I am also a mother of 3 very, very active teens (20, 17 and 15), a wife, home maker....I assist as a care giver to my mom that is in mid stage alzheimers, care giver to our pets.....and am always seeking time to paint, animate or be creative is some way -

I NEED TO BOOST MY ENERGY!  Eliminate this sleeping issue, and ensure that I don't have any medical problems (besides apnea) that may be causing these symptoms......Worried about cardiac issues, or other neurological issues.....

Advice is appreciated....I will be going back to the doctor asap....but just wanted to see if anyone out there has had a similiar experience and may be able to suggest a treatment, or dietary supplement that can improve my health.