Wow, I haven't experienced the kinds of stress and grief you are dealing with...
I have found meditation to be helpful, especially the kind called Mindfulness or Vipassana. I found a good audio tape by David Kabat Zinn called something like Wherever You Go There You Are. Turning attention to one's breathing can be a powerful way to reduce stress, and you can do at anytime for even a few seconds. It gets better with practice. Not breathing differently, but just noticing the breathing itself, the way it feels in different areas of your body and things like whether it's fast or slow, dep or shallow, etc,
Emotional & social support are important at a time like this. Have you considered a support group or counseling? If those aren't feasible, I can vouch for Overeaters Anonymous online meetings being a helpful way to stay focused on a new WOE. It's free & anonymous.
And of course here on 3FC