ray~ i know all too well what you are going thru. iam 37 and a mother of two girls(11,13). iwas diagnosed with metastatic lung cancer almost a year ago. those same thoughts raced thru my head day and night.
finally after many prayers god has given me peace about it. unfortunately my cancer is very rare and there a virtually no treatments that are successful. although i am trying them anyway. iam not giving up. as you know there is too much to live for.
once diagnosed i took the kids to counselers and it helped. i am very up front and honest with them(to certain degree-i would never tell them the prognosis) but with the advice of the counselor they seem to better when you let them in on what is going rather than keeping it from them because they can tell.
kids are amazingly strong. somedays they are stronger than i am. i also informed there teachers at school so they could keep and eye to see if they seemd bothered by it or changed any. hopefully i am passing this on to you and you will never need it. god does give us incredible strength when we ask.
i dont know if this helped at all but i will be praying for you and your family and you can come and vent here any time. we all understand...........