I have heard the term mindfulness used a fair bit around me since the accident. Then a friend pointed out that perhaps, I'm abbreviating here, mindfulness is actually gratitude. I can't say I'm sure that one excludes the other but the point was that a better description of my state of mind might be "gratitude."
I am not fond of quoting definitions but in this case allow me to make an exception to my rule...from Wikipedia to keep it simple:
Mindfulness is the psychological process of bringing one's attention to experiences occurring in the present moment, which one can develop through the practice of meditation and through other training.
Keeping that description in mind I don't see any mention of gratitude so perhaps there is a distinction worth bearing in mind.