I hate to say it, but you're in a community where we really understand what you're feeling and your circumstances.
I only have 1 DD also. (and 1 stepson). That is the worst part that it's the only one we have. It's hard to tell by your post if you've attempted contact (I assume yes) and have just been repeatedly shunned or what.
The long distance makes it doubly hard.
I am so sorry for the loss of your DD and GC. I don't know the circumstances as to what happened or why, but I hope that in time, things will change for you. If they don't, please concentrate on yourself, your needs, and your wants.
I, too, have felt those envy pangs when I hear other mom's my age talk about their AC that are my DD's age and how well they're doing. Mine, not so hot. I am happy for them and feel proud for them especially when I know those kids from when they were babes, but I look at my own and feel terrible some days.
I am wishing you well. It is really helpful to post here and let our your feelings. You'll find awesome WW that will encourage and support you....and sometimes you might just needs us to listen. That's OK too.
Warmest thoughts to you bugaluggs.