Dbh,
I am so sorry for your pain. My sister commited suicide as well. I didn't really allow myself to grieve her loss, instead I dove into a sick relationship with my XA, maybe to punish myself, maybe to distract myself from thinking about her.
I really wish I had gone to a support group for survivors of suicide and joined SR instead. I'm glad you are here.
I know what you mean about feeling like the people in the group might not understand, and that their circumstances were different. Suicide is weird in the way it hits hard in such a personal way. It's an isolating kind of pain. That's why I think you should fight against your uncomfortability with the support group and force yourself to go. You need to deal with this grief or it will infect your life in other ways.
My sister was depressed for years and her suicide always felt kind of inevitable to me. The rest of my family was more optimistic but I always felt like she was a freight train on a collision course with disaster. I think it is harder when it comes totally out of the blue, and of course when there is a child left behind that is the biggest tragedy of all.
All we can truly do in life when we come from these crazy families is focus on surviving ourselves. Even if in hindsight you feel like you could have done more, you did the best you could do at that time. You didn't go through your life intentionally not doing enough for your depressed sister. I really see you as an equal victim of the tragedy.
Forgive your sister for what she did. She was very sick and in pain. If you can forgive her, I believe it will be easier to then forgive yourself.
I wish I could write more. I freeze up when I try to talk about suicide and obviously have a lot more work to do with my own grief.
One last thing, I believe pain is stored in the body so I embraced yoga as an indirect and less frightening way to face mine. Yoga has really helped me release a lot of it.
Love and hugs to you. PM me anytime if you want.