@sazbe Welcome to the community. I'm in awe of anyone who can go back to work in the early days after diagnosis. It's such an overwhelming time. You're obviously up on the medical side of things but you may not be aware of how deeply it rocks so many so don't be surprised at the emotional upheaval. I would suggest that you tell the kids what is going on as soon as you can as they will know that something is wrong and may think things are worse than they are (!!!) or think it is to do with them. Mine were 11, 12 & 15 at the time of diagnosis and I had to tell them immediately as the two youngest were in the car as we raced from Breastscreen to my GP who was staying late to wait for us. They have grown up knowing that they never met their auntie, my sister, as she died young from breast cancer so they've always known it is a serious disease. I think that giving them the knowledge of what was going on at each stage (basic and no what-ifs) has enabled them to cope better and to understand and support me. Kids always know when something is going on and secrets can be terrifying. CanTeen have good resources for telling kids of all ages.
It also sounds as if you may find release in writing, given the eloquency of your post. Perhaps consider a journal or blog. I started a blog to keep friends and family informed (so I didn't have to answer questions all the time) and I found it quite cathartic during the year of active treatment. It became as much of journal as information provision and looking back at it, I am amazed at how much I have forgotten and what I was thinking at the time. You won't find it in a search as the settings are private but I provide the address to those who are interested.
I am glad that you have found us as this forum may just be what gets you through treatment in relatively good shape. Everyone here gets it. And so many in the medical community seem to be dismissive of this site which is unfortunate.