Honestly the only thing that helped me was No Contact. And you see how angry I am still with the moderately increased contact we've had due to the kids.
Also when the weather was good I made myself go out and try to run. Sometimes my heart was so heavy I could only walk. Sometimes it was so heavy I could walk to a bench, sit and cry, then get up and walk to the next bench and try not to cry. Then I'd jog past two benches and walk to the third one. But I did try to get out and get a lot of exercise.
I made playlists of music that made me feel good about myself. Labug and a few others mentioned some -- Roar by Katy Perry, Brave by Sara Bareilles -- that were inspirational and particular to my sitch. "Tell Me What You See" by the Beatles is a song that I always imagine being a reminder to me that I get to choose how I see the world, and "On Top of the World" by Imagine Dragons was a feeling I aspired to. And of course "Living In the Moment" by Jason Mraz. Those helped me remember what I was (am) aiming for. I just keep adding to the list as I find applicable ones.
Maybe once your son has been through this health issue you'll be able to pull way back from your W and find peace. I can't imagine how hard it is to move with all this hanging over you. I'm sorry.
Me42, H40 D12, S8, S7 A revealed: 7/13 Sep 4/14; Agreed to D 1/15