Hi Craig2004.  Sorry to hear about your diagnosis.  I can't tell you what will happen in the future, nobody can and the doctors get it wrong sometimes too.  People are living a lot longer with stage 4 cancer now.  There are new treatments and trials coming out all the time.  I have stage 4 breast cancer and my oncologist said that the mind is a powerful tool and I believe him.  I am living a good life and enjoying holidays etc.  I have tried to find out as much as I can about my cancer as I can then question my oncologist about treatments etc.  I am sorry that you feel low and it is good that you have reached out on here.  I got some counselling that Macmillan arranged for me.  The Macmillan website has a kidney cancer forum and also a Living with Incurable cancer - patients only forum.  It is good to chat to other people who are going through the same thing and know how you feel.  They also have  helpline on here that you can phone to talk to someone.
Lee x