Oh mighty-mama....I am so deeply sorry for your loss!! I know the pain you are going through. Tomorrow will be my brother's memorial service. I can't imagine that 6 weeks have gone by. It's unreal that the world has kept going even though we have all been sheltered in our grief......and yet, I know that this is how it is supposed to be......we MUST go on, one step, one moment, one day, at a time. Our time is here and now... Somewhere, amidst all the grief, is a deep well of happy times, cherished memories and quirky fun stories (just like you and your sister shared). Although that time may not be right now, I think that is a worthy goal to work towards.... A time when some of the pain will numb (with time) and the special moments will resurface.
I'm not entirely there myself, but I can catch glimpses of it. Each time I look at our childhood pictures an entire barrage of moments flies through my head.....things I haven't thought of in years! They are special and precious moments....like when we rode our bikes to get our first dog, a big fat beagle named Loki. Of course, since this is all so raw, remembering those special moments that exist between siblings is followed by tears....but that is normal. You cry, you grieve, you ask "Why!?", etc, etc,....then you wipe away your tears and do something mundane....like feed the kids, wash the dishes.....and you realize that life continues to go on and you need to find a way to go on with it....
I truly feel for you and for your sister's family. My heart bleeds for those little boys, for her dh and for you. It is palpably obvious that you and she had a lovely relationship, the kind that transcends this tragedy.
I don't know what your thoughts are on the afterlife, but, for me there has been some measure of comfort reading about where our loved ones go and how they return to us to comfort, guide and simply "be" with us. I went to Borders and stocked up on some books written by mediums that delve into the after life. Maybe I'm just grasping, but I truly believe that our loved ones come back to us. I thought this before our tragedy hit, and I believe even more now. Your feeling that your sister is with you is more than wishful thinking.
We have received so many "signs" from my brother that it makes me both happy to know that he is communicating with me and sad that this communication is not the way it used to be. Of course, there is always that tiny bit of logic in me that thinks that maybe I'm finding and looking for signs where none exist. But, whether that is the case or not, it offers comfort and solace when nothing else seems to do that. So, I settle for the special dreams and the tiny signs I get every so often....they make sense to me.
I think your sister is letting you "feel" her presence, letting you know that you are not alone. I know that this knowledge probably just skims the surface of your grief, but it is a morsel of hope, I think, that our loved ones are inextricably drawn to us and do not truly leave us. They leave us on this physical earth but continue to return again and again and again, as long as we need them. I think this is especially the case when young people (including children) leave this earth. Their story is not finished and they have work to complete here with us.
Nevertheless, it is sad and tragic for the rest of us that need to figure out, as you so aptly put it, "how to live without" them. I don't have the answer, but I know that there must be a way and that their legacy will change us (hopefully for the better) for the rest of our lives.
Sending you my heartfelt condolences and wishing for you to find some measure of peace in the future.