Right on, Charm! - I think it's ok to mourn a loss and to feel compassion for oneself for what cancer has taken away. Hopefully, the mourning can allow at some point for the more positive thoughts to be given a turn. A journal is a good idea because even if no one were ever to read it, at least you have assigned it a spot - a compartment in your life - that you can revisit if you so choose but that will allow room for life to go on and for more positive thoughts to take hold. I used to keep a list of funny experiences I remembered or pics that made me smile. I especially liked one of the little penguin who gets knocked down but he gets up and keeps on going. And he's still here:

http://webpages.charter.net/xila/favimages.html