Are there any support groups for a sister who found her sister passed away...?

I lost my sister on 01/14/09. Im 24 and was 22 at the time with a 8 month old daughter My sisters autopsy showed nothing at all... she was never sick no drugs not suicide. The medical examiner couldn't tell us why she passed away even to this day my family and I have no idea why she passed. She was healthy and happy her and I were best friends we spent every single together and she was helping me raise my daughter.... on that morning it was only her and I home alone. She passed away at about 9:02am and I didn't find her until about 11:46am. walking into that room and finding her the way I did has really screwed me up now. I suffer from PTSD anxiety and depression. Im looking for a support group for all this.. Ive tried support groups for PTSD and they didnt help I tried groups for people who had lost siblings and it hasn't helped. Im truly in need of a support where other people understand what Ive been through but as you can imagine its not easy to find others like myself.. if anyone has any suggestions at all please please please comment here.. and thank you to everyone!!!