Dear Fireballkid,
I know exactly how you feel. My brother took his own life and I look back and think of all the What If's and it about drove me insane. Everything was so clear after he died of how he was reaching out. I even noticed things weren't right, but I never thought in a million years I would ever wake up to that horrifying phone call. Something that helped me cope was hearing if it wasn't meant to happen, it wouldn't have happened. It took a long time to accept that, but it helped me get over that bump. All we can do after this learning experience is make sure we are there for the future and reach out if we get the slightest thought in our head so we can honestly say we did everything we could. I'm very sorry to hear about your sister. My brother and I were very close and I miss him tremendously.