Hugs, Sheila. I think it's way harder to let go of what could have been than letting go of what is. I get the same feelings. DS's classmates all seemed to get little brothers or sisters this past year. I had begged and begged XAH for another child. Even seeing my friends all tired and harried didn't make it any easier to acknowledge that I will never have another baby and DS will never be a big brother.
Yeah, it may be for the best, but it still hurts. *sigh*. Snuggle you little 9mo and I'll give my 6yo a big old bear hug.