The book, "The invaluable guide to life after stroke, an owner's manual"   I found a most important part that refers to lability.  "The stroke reduced the power to restrain your emotion, rather than losing your stability, you gain heightened sensitivity", A statement I agree with totally.  It also means that your emotional "guard" is not in control anymore.
I still have (To a lesser degree of course) after 7 years post stroke, have extreme lability and tend to overreact to any emotion whether it be happy, sad, anger, frustration, prior memories, future worries, startle response...whatever.  This condition has been just as big of a problem to me as losing the use of my left hand.
During my stay in the hospital, I was never told why I was crying so much, laughing out of control, etc.  I was lead to believe it came from not coping well...showing the lack of knowledge of my PT's and OT's then.  It helped me tremendously to know it was not depression, just lability.  The lability has lessened with time but remains a big problem.  There is a big difference between depression and lability.
Both can be helped with mood meds like Paxil or Zoloft etc, if you feel the need to.  As a side note I have also found that my emotions follow the natural body biorhythms, 27-28 day cycles.  If I do find I'm depressed, weepy usually.  I check my biorhythm and if it shows I'm at my low point, then I feel better just in knowing it will rise soon.  This is  natures way.  Great help also.
I still search for imformation on how to aid improvement the lack of real knowledge out there, I still find very frustrating, as I'm sure others do as well.  I have found The American Heart Association's magazine is very helpful as well as the The National Stroke Association's magazine.  I've found both to be very informative for newcomers, caregivers as well as for stroke veterans.  I encourage them to subscribe to both, especially in those first few crucial months.  Knowledge is a good healer.  Just by knowing there're others out there that have been on this journey and have found ways to adapt, cope and move forward in the best way as possible is motivating in itself.  What I have found has  helped me in my own rehab.

II